Eye imaging in head worn computing

ABSTRACT

Aspects of the present invention relate to methods and systems for imaging, recognizing, and tracking of a user&#39;s eye that is wearing a HWC. Aspects further relate to the processing of images reflected from the user&#39;s eye and controlling displayed content in accordance therewith.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to and is a continuationof U.S. non-provisional application Ser. No. 14/218,606, filed Mar. 18,2014.

U.S. non-provisional application Ser. No. 14/218,606, filed Mar. 18,2014 is a continuation-in-part of U.S. non-provisional application Ser.No. 14/216,175, filed Mar. 17, 2014.

U.S. non-provisional application Ser. No. 14/216,175 is acontinuation-in-part of the following three U.S. patent applications:

-   -   U.S. non-provisional application Ser. No. 14/160,377, entitled        Optical Configurations for Head Worn Computing, filed Jan. 21,        2014;    -   U.S. non-provisional application Ser. No. 14/172,901, entitled        Optical Configurations for Head Worn Computing, filed Feb. 4,        2014, which is a continuation-in-part of application Ser. No.        14/163,646, filed Jan. 24, 2014 and U.S. non-provisional        application Ser. No. 14/160,377, filed Jan. 21, 2014; and    -   U.S. non-provisional application Ser. No. 14/181,459, entitled        Suppression of Stray Light in Head Worn Computing, filed Feb.        14, 2014, which is a continuation-in-part of U.S.        non-provisional application Ser. No. 14/178,047, filed Feb. 11,        2014, U.S. non-provisional application Ser. No. 14/172,901,        filed Feb. 4, 2014, U.S. non-provisional application Ser. No.        14/163,646, filed Jan. 24, 2014 and U.S. non-provisional        application Ser. No. 14/160,377, filed Jan. 21, 2014.

Each of the above applications are hereby incorporated by reference intheir entirety.

BACKGROUND

Field of the Invention

This invention relates to head worn computing. More particularly, thisinvention relates to eye imaging in head worn computing.

Description of Related Art

Wearable computing systems have been developed and are beginning to becommercialized. Many problems persist in the wearable computing fieldthat need to be resolved to make them meet the demands of the market.

SUMMARY

Aspects of the present invention relate to methods and systems forimaging, recognizing, and tracking of a user's eye that is wearing aHWC. Aspects further relate to the processing of images reflected fromthe user's eye and controlling displayed content in accordancetherewith.

These and other systems, methods, objects, features, and advantages ofthe present invention will be apparent to those skilled in the art fromthe following detailed description of the preferred embodiment and thedrawings. All documents mentioned herein are hereby incorporated intheir entirety by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are described with reference to the following Figures. Thesame numbers may be used throughout to reference like features andcomponents that are shown in the Figures:

FIG. 1 illustrates a head worn computing system in accordance with theprinciples of the present invention.

FIG. 2 illustrates a head worn computing system with optical system inaccordance with the principles of the present invention.

FIG. 3a illustrates a large prior art optical arrangement.

FIG. 3b illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 4 illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 4a illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 4b illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 5 illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 5a illustrates an upper optical module in accordance with theprinciples of the present invention.

FIG. 5b illustrates an upper optical module and dark light trapaccording to the principles of the present invention.

FIG. 5c illustrates an upper optical module and dark light trapaccording to the principles of the present invention.

FIG. 5d illustrates an upper optical module and dark light trapaccording to the principles of the present invention.

FIG. 5e illustrates an upper optical module and dark light trapaccording to the principles of the present invention.

FIG. 6 illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 7 illustrates angles of combiner elements in accordance with theprinciples of the present invention.

FIG. 8 illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 8a illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 8b illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 8c illustrates upper and lower optical modules in accordance withthe principles of the present invention.

FIG. 9 illustrates an eye imaging system in accordance with theprinciples of the present invention.

FIG. 10 illustrates a light source in accordance with the principles ofthe present invention.

FIG. 10a illustrates a back lighting system in accordance with theprinciples of the present invention.

FIG. 10b illustrates a back lighting system in accordance with theprinciples of the present invention.

FIGS. 11a to 11d illustrate light source and filters in accordance withthe principles of the present invention.

FIGS. 12a to 12c illustrate light source and quantum dot systems inaccordance with the principles of the present invention.

FIGS. 13a to 13c illustrate peripheral lighting systems in accordancewith the principles of the present invention.

FIGS. 14a to 14c illustrate a light suppression systems in accordancewith the principles of the present invention.

FIG. 15 illustrates an external user interface in accordance with theprinciples of the present invention.

FIGS. 16a to 16c illustrate distance control systems in accordance withthe principles of the present invention.

FIGS. 17a to 17c illustrate force interpretation systems in accordancewith the principles of the present invention.

FIGS. 18a to 18c illustrate user interface mode selection systems inaccordance with the principles of the present invention.

FIG. 19 illustrates interaction systems in accordance with theprinciples of the present invention.

FIG. 20 illustrates external user interfaces in accordance with theprinciples of the present invention.

FIG. 21 illustrates mD trace representations presented in accordancewith the principles of the present invention.

FIG. 22 illustrates mD trace representations presented in accordancewith the principles of the present invention.

FIG. 23 illustrates an mD scanned environment in accordance with theprinciples of the present invention.

FIG. 23a illustrates mD trace representations presented in accordancewith the principles of the present invention.

FIG. 24 illustrates a stray light suppression technology in accordancewith the principles of the present invention.

FIG. 25 illustrates a stray light suppression technology in accordancewith the principles of the present invention.

FIG. 26 illustrates a stray light suppression technology in accordancewith the principles of the present invention.

FIG. 27 illustrates a stray light suppression technology in accordancewith the principles of the present invention.

FIGS. 28a to 28c illustrate DLP mirror angles.

FIGS. 29 to 33 illustrate eye imaging systems according to theprinciples of the present invention.

FIGS. 34 and 34 a illustrate structured eye lighting systems accordingto the principles of the present invention.

FIG. 35 illustrates eye glint in the prediction of eye directionanalysis in accordance with the principles of the present invention.

FIG. 36a illustrates eye characteristics that may be used in personalidentification through analysis of a system according to the principlesof the present invention.

FIG. 36b illustrates a digital content presentation reflection off ofthe wearer's eye that may be analyzed in accordance with the principlesof the present invention.

FIG. 37 illustrates eye imaging along various virtual target lines andvarious focal planes in accordance with the principles of the presentinvention.

FIG. 38 illustrates content control with respect to eye movement basedon eye imaging in accordance with the principles of the presentinvention.

FIG. 39 illustrates eye imaging and eye convergence in accordance withthe principles of the present invention.

While the invention has been described in connection with certainpreferred embodiments, other embodiments would be understood by one ofordinary skill in the art and are encompassed herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Aspects of the present invention relate to head-worn computing (“HWC”)systems. HWC involves, in some instances, a system that mimics theappearance of head-worn glasses or sunglasses. The glasses may be afully developed computing platform, such as including computer displayspresented in each of the lenses of the glasses to the eyes of the user.In embodiments, the lenses and displays may be configured to allow aperson wearing the glasses to see the environment through the lenseswhile also seeing, simultaneously, digital imagery, which forms anoverlaid image that is perceived by the person as a digitally augmentedimage of the environment, or augmented reality (“AR”).

HWC involves more than just placing a computing system on a person'shead. The system may need to be designed as a lightweight, compact andfully functional computer display, such as wherein the computer displayincludes a high resolution digital display that provides a high level ofemersion comprised of the displayed digital content and the see-throughview of the environmental surroundings. User interfaces and controlsystems suited to the HWC device may be required that are unlike thoseused for a more conventional computer such as a laptop. For the HWC andassociated systems to be most effective, the glasses may be equippedwith sensors to determine environmental conditions, geographic location,relative positioning to other points of interest, objects identified byimaging and movement by the user or other users in a connected group,and the like. The HWC may then change the mode of operation to match theconditions, location, positioning, movements, and the like, in a methodgenerally referred to as a contextually aware HWC. The glasses also mayneed to be connected, wirelessly or otherwise, to other systems eitherlocally or through a network. Controlling the glasses may be achievedthrough the use of an external device, automatically throughcontextually gathered information, through user gestures captured by theglasses sensors, and the like. Each technique may be further refineddepending on the software application being used in the glasses. Theglasses may further be used to control or coordinate with externaldevices that are associated with the glasses.

Referring to FIG. 1, an overview of the HWC system 100 is presented. Asshown, the HWC system 100 comprises a HWC 102, which in this instance isconfigured as glasses to be worn on the head with sensors such that theHWC 102 is aware of the objects and conditions in the environment 114.In this instance, the HWC 102 also receives and interprets controlinputs such as gestures and movements 116. The HWC 102 may communicatewith external user interfaces 104. The external user interfaces 104 mayprovide a physical user interface to take control instructions from auser of the HWC 102 and the external user interfaces 104 and the HWC 102may communicate bi-directionally to affect the user's command andprovide feedback to the external device 108. The HWC 102 may alsocommunicate bi-directionally with externally controlled or coordinatedlocal devices 108. For example, an external user interface 104 may beused in connection with the HWC 102 to control an externally controlledor coordinated local device 108. The externally controlled orcoordinated local device 108 may provide feedback to the HWC 102 and acustomized GUI may be presented in the HWC 102 based on the type ofdevice or specifically identified device 108. The HWC 102 may alsointeract with remote devices and information sources 112 through anetwork connection 110. Again, the external user interface 104 may beused in connection with the HWC 102 to control or otherwise interactwith any of the remote devices 108 and information sources 112 in asimilar way as when the external user interfaces 104 are used to controlor otherwise interact with the externally controlled or coordinatedlocal devices 108. Similarly, HWC 102 may interpret gestures 116 (e.g.captured from forward, downward, upward, rearward facing sensors such ascamera(s), range finders, IR sensors, etc.) or environmental conditionssensed in the environment 114 to control either local or remote devices108 or 112.

We will now describe each of the main elements depicted on FIG. 1 inmore detail; however, these descriptions are intended to provide generalguidance and should not be construed as limiting. Additional descriptionof each element may also be further described herein.

The HWC 102 is a computing platform intended to be worn on a person'shead. The HWC 102 may take many different forms to fit many differentfunctional requirements. In some situations, the HWC 102 will bedesigned in the form of conventional glasses. The glasses may or may nothave active computer graphics displays. In situations where the HWC 102has integrated computer displays the displays may be configured assee-through displays such that the digital imagery can be overlaid withrespect to the user's view of the environment 114. There are a number ofsee-through optical designs that may be used, including ones that have areflective display (e.g. LCoS, DLP), emissive displays (e.g. OLED, LED),hologram, TIR waveguides, and the like. In embodiments, lighting systemsused in connection with the display optics may be solid state lightingsystems, such as LED, OLED, quantum dot, quantum dot LED, etc. Inaddition, the optical configuration may be monocular or binocular. Itmay also include vision corrective optical components. In embodiments,the optics may be packaged as contact lenses. In other embodiments, theHWC 102 may be in the form of a helmet with a see-through shield,sunglasses, safety glasses, goggles, a mask, fire helmet withsee-through shield, police helmet with see through shield, militaryhelmet with see-through shield, utility form customized to a certainwork task (e.g. inventory control, logistics, repair, maintenance,etc.), and the like.

The HWC 102 may also have a number of integrated computing facilities,such as an integrated processor, integrated power management,communication structures (e.g. cell net, WiFi, Bluetooth, local areaconnections, mesh connections, remote connections (e.g. client server,etc.)), and the like. The HWC 102 may also have a number of positionalawareness sensors, such as GPS, electronic compass, altimeter, tiltsensor, IMU, and the like. It may also have other sensors such as acamera, rangefinder, hyper-spectral camera, Geiger counter, microphone,spectral illumination detector, temperature sensor, chemical sensor,biologic sensor, moisture sensor, ultrasonic sensor, and the like.

The HWC 102 may also have integrated control technologies. Theintegrated control technologies may be contextual based control, passivecontrol, active control, user control, and the like. For example, theHWC 102 may have an integrated sensor (e.g. camera) that captures userhand or body gestures 116 such that the integrated processing system caninterpret the gestures and generate control commands for the HWC 102. Inanother example, the HWC 102 may have sensors that detect movement (e.g.a nod, head shake, and the like) including accelerometers, gyros andother inertial measurements, where the integrated processor mayinterpret the movement and generate a control command in response. TheHWC 102 may also automatically control itself based on measured orperceived environmental conditions. For example, if it is bright in theenvironment the HWC 102 may increase the brightness or contrast of thedisplayed image. In embodiments, the integrated control technologies maybe mounted on the HWC 102 such that a user can interact with itdirectly. For example, the HWC 102 may have a button(s), touchcapacitive interface, and the like.

As described herein, the HWC 102 may be in communication with externaluser interfaces 104. The external user interfaces may come in manydifferent forms. For example, a cell phone screen may be adapted to takeuser input for control of an aspect of the HWC 102. The external userinterface may be a dedicated UI, such as a keyboard, touch surface,button(s), joy stick, and the like. In embodiments, the externalcontroller may be integrated into another device such as a ring, watch,bike, car, and the like. In each case, the external user interface 104may include sensors (e.g. IMU, accelerometers, compass, altimeter, andthe like) to provide additional input for controlling the HWD 104.

As described herein, the HWC 102 may control or coordinate with otherlocal devices 108. The external devices 108 may be an audio device,visual device, vehicle, cell phone, computer, and the like. Forinstance, the local external device 108 may be another HWC 102, whereinformation may then be exchanged between the separate HWCs 108.

Similar to the way the HWC 102 may control or coordinate with localdevices 106, the HWC 102 may control or coordinate with remote devices112, such as the HWC 102 communicating with the remote devices 112through a network 110. Again, the form of the remote device 112 may havemany forms. Included in these forms is another HWC 102. For example,each HWC 102 may communicate its GPS position such that all the HWCs 102know where all of HWC 102 are located.

FIG. 2 illustrates a HWC 102 with an optical system that includes anupper optical module 202 and a lower optical module 204. While the upperand lower optical modules 202 and 204 will generally be described asseparate modules, it should be understood that this is illustrative onlyand the present invention includes other physical configurations, suchas that when the two modules are combined into a single module or wherethe elements making up the two modules are configured into more than twomodules. In embodiments, the upper module 202 includes a computercontrolled display (e.g. LCoS, DLP, OLED, etc.) and image light deliveryoptics. In embodiments, the lower module includes eye delivery opticsthat are configured to receive the upper module's image light anddeliver the image light to the eye of a wearer of the HWC. In FIG. 2, itshould be noted that while the upper and lower optical modules 202 and204 are illustrated in one side of the HWC such that image light can bedelivered to one eye of the wearer, that it is envisioned by the presentinvention that embodiments will contain two image light deliverysystems, one for each eye.

FIG. 3b illustrates an upper optical module 202 in accordance with theprinciples of the present invention. In this embodiment, the upperoptical module 202 includes a DLP (also known as DMD or digitalmicromirror device) computer operated display 304 which includes pixelscomprised of rotatable mirrors (such as, for example, the DLP3000available from Texas Instruments), polarized light source 302, ¼ waveretarder film 308, reflective polarizer 310 and a field lens 312. Thepolarized light source 302 provides substantially uniform polarizedlight that is generally directed towards the reflective polarizer 310.The reflective polarizer reflects light of one polarization state (e.g.S polarized light) and transmits light of the other polarization state(e.g. P polarized light). The polarized light source 302 and thereflective polarizer 310 are oriented so that the polarized light fromthe polarized light source 302 is reflected generally towards the DLP304. The light then passes through the ¼ wave film 308 once beforeilluminating the pixels of the DLP 304 and then again after beingreflected by the pixels of the DLP 304. In passing through the ¼ wavefilm 308 twice, the light is converted from one polarization state tothe other polarization state (e.g. the light is converted from S to Ppolarized light). The light then passes through the reflective polarizer310. In the event that the DLP pixel(s) are in the “on” state (i.e. themirrors are positioned to reflect light towards the field lens 312, the“on” pixels reflect the light generally along the optical axis and intothe field lens 312. This light that is reflected by “on” pixels andwhich is directed generally along the optical axis of the field lens 312will be referred to as image light 316. The image light 316 then passesthrough the field lens to be used by a lower optical module 204.

The light that is provided by the polarized light source 302, which issubsequently reflected by the reflective polarizer 310 before itreflects from the DLP 304, will generally be referred to as illuminationlight. The light that is reflected by the “off” pixels of the DLP 304 isreflected at a different angle than the light reflected by the “on”pixels, so that the light from the “off” pixels is generally directedaway from the optical axis of the field lens 312 and toward the side ofthe upper optical module 202 as shown in FIG. 3. The light that isreflected by the “off” pixels of the DLP 304 will be referred to as darkstate light 314.

The DLP 304 operates as a computer controlled display and is generallythought of as a MEMs device. The DLP pixels are comprised of smallmirrors that can be directed. The mirrors generally flip from one angleto another angle. The two angles are generally referred to as states.When light is used to illuminate the DLP the mirrors will reflect thelight in a direction depending on the state. In embodiments herein, wegenerally refer to the two states as “on” and “off,” which is intendedto depict the condition of a display pixel. “On” pixels will be seen bya viewer of the display as emitting light because the light is directedalong the optical axis and into the field lens and the associatedremainder of the display system. “Off” pixels will be seen by a viewerof the display as not emitting light because the light from these pixelsis directed to the side of the optical housing and into a light trap orlight dump where the light is absorbed. The pattern of “on” and “off”pixels produces image light that is perceived by a viewer of the displayas a computer generated image. Full color images can be presented to auser by sequentially providing illumination light with complimentarycolors such as red, green and blue. Where the sequence is presented in arecurring cycle that is faster than the user can perceive as separateimages and as a result the user perceives a full color image comprisedof the sum of the sequential images. Bright pixels in the image areprovided by pixels that remain in the “on” state for the entire time ofthe cycle, while dimmer pixels in the image are provided by pixels thatswitch between the “on” state and “off” state within the time of thecycle, or frame time when in a video sequence of images.

FIG. 3a shows an illustration of a system for a DLP 304 in which theunpolarized light source 350 is pointed directly at the DLP 304. In thiscase, the angle required for the illumination light is such that thefield lens 352 must be positioned substantially distant from the DLP 304to avoid the illumination light from being clipped by the field lens352. The large distance between the field lens 352 and the DLP 304 alongwith the straight path of the dark state light 354, means that the lighttrap for the dark state light 354 is also located at a substantialdistance from the DLP. For these reasons, this configuration is largerin size compared to the upper optics module 202 of the preferredembodiments.

The configuration illustrated in FIG. 3b can be lightweight and compactsuch that it fits into a small portion of a HWC. For example, the uppermodules 202 illustrated herein can be physically adapted to mount in anupper frame of a HWC such that the image light can be directed into alower optical module 204 for presentation of digital content to awearer's eye. The package of components that combine to generate theimage light (i.e. the polarized light source 302, DLP 304, reflectivepolarizer 310 and ¼ wave film 308) is very light and is compact. Theheight of the system, excluding the field lens, may be less than 8 mm.The width (i.e. from front to back) may be less than 8 mm. The weightmay be less than 2 grams. The compactness of this upper optical module202 allows for a compact mechanical design of the HWC and the lightweight nature of these embodiments help make the HWC lightweight toprovide for a HWC that is comfortable for a wearer of the HWC.

The configuration illustrated in FIG. 3b can produce sharp contrast,high brightness and deep blacks, especially when compared to LCD or LCoSdisplays used in HWC. The “on” and “off” states of the DLP provide for astrong differentiator in the light reflection path representing an “on”pixel and an “off” pixel. As will be discussed in more detail below, thedark state light from the “off” pixel reflections can be managed toreduce stray light in the display system to produce images with highcontrast.

FIG. 4 illustrates another embodiment of an upper optical module 202 inaccordance with the principles of the present invention. This embodimentincludes a light source 404, but in this case, the light source canprovide unpolarized illumination light. The illumination light from thelight source 404 is directed into a TIR wedge 418 such that theillumination light is incident on an internal surface of the TIR wedge418 (shown as the angled lower surface of the TRI wedge 418 in FIG. 4)at an angle that is beyond the critical angle as defined by Eqn 1.Critical angle=arc−sin(1/n)  Eqn 1

Where the critical angle is the angle beyond which the illuminationlight is reflected from the internal surface when the internal surfacecomprises an interface from a solid with a higher refractive index (n)to air with a refractive index of 1 (e.g. for an interface of acrylic,with a refractive index of n=1.5, to air, the critical angle is 41.8degrees; for an interface of polycarbonate, with a refractive index ofn=1.59, to air the critical angle is 38.9 degrees). Consequently, theTIR wedge 418 is associated with a thin air gap 408 along the internalsurface to create an interface between a solid with a higher refractiveindex and air. By choosing the angle of the light source 404 relative tothe DLP 402 in correspondence to the angle of the internal surface ofthe TIR wedge 418, illumination light is turned toward the DLP 402 at anangle suitable for providing image light 414 as reflected from “on”pixels. Wherein, the illumination light is provided to the DLP 402 atapproximately twice the angle of the pixel mirrors in the DLP 402 thatare in the “on” state, such that after reflecting from the pixelmirrors, the image light 414 is directed generally along the opticalaxis of the field lens. Depending on the state of the DLP pixels, theillumination light from “on” pixels may be reflected as image light 414which is directed towards a field lens and a lower optical module 204,while illumination light reflected from “off” pixels (generally referredto herein as “dark” state light, “off” pixel light or “off” state light)410 is directed in a separate direction, which may be trapped and notused for the image that is ultimately presented to the wearer's eye.

The light trap for the dark state light 410 may be located along theoptical axis defined by the direction of the dark state light 410 and inthe side of the housing, with the function of absorbing the dark statelight. To this end, the light trap may be comprised of an area outsideof the cone of image light 414 from the “on” pixels. The light trap istypically made up of materials that absorb light including coatings ofblack paints or other light absorbing materials to prevent lightscattering from the dark state light degrading the image perceived bythe user. In addition, the light trap may be recessed into the wall ofthe housing or include masks or guards to block scattered light andprevent the light trap from being viewed adjacent to the displayedimage.

The embodiment of FIG. 4 also includes a corrective wedge 420 to correctthe effect of refraction of the image light 414 as it exits the TIRwedge 418. By including the corrective wedge 420 and providing a thinair gap 408 (e.g. 25 micron), the image light from the “on” pixels canbe maintained generally in a direction along the optical axis of thefield lens (i.e. the same direction as that defined by the image light414) so it passes into the field lens and the lower optical module 204.As shown in FIG. 4, the image light 414 from the “on” pixels exits thecorrective wedge 420 generally perpendicular to the surface of thecorrective wedge 420 while the dark state light exits at an obliqueangle. As a result, the direction of the image light 414 from the “on”pixels is largely unaffected by refraction as it exits from the surfaceof the corrective wedge 420. In contrast, the dark state light 410 issubstantially changed in direction by refraction when the dark statelight 410 exits the corrective wedge 420.

The embodiment illustrated in FIG. 4 has the similar advantages of thosediscussed in connection with the embodiment of FIG. 3b . The dimensionsand weight of the upper module 202 depicted in FIG. 4 may beapproximately 8×8 mm with a weight of less than 3 grams. A difference inoverall performance between the configuration illustrated in FIG. 3b andthe configuration illustrated in FIG. 4 is that the embodiment of FIG. 4doesn't require the use of polarized light as supplied by the lightsource 404. This can be an advantage in some situations as will bediscussed in more detail below (e.g. increased see-through transparencyof the HWC optics from the user's perspective). Polarized light may beused in connection with the embodiment depicted in FIG. 4, inembodiments. An additional advantage of the embodiment of FIG. 4compared to the embodiment shown in FIG. 3b is that the dark state light(shown as DLP off light 410) is directed at a steeper angle away fromthe optical axis of the image light 414 due to the added refractionencountered when the dark state light 410 exits the corrective wedge420. This steeper angle of the dark state light 410 allows for the lighttrap to be positioned closer to the DLP 402 so that the overall size ofthe upper module 202 can be reduced. The light trap can also be madelarger since the light trap doesn't interfere with the field lens,thereby the efficiency of the light trap can be increased and as aresult, stray light can be reduced and the contrast of the imageperceived by the user can be increased. FIG. 4a illustrates theembodiment described in connection with FIG. 4 with an example set ofcorresponding angles at the various surfaces with the reflected anglesof a ray of light passing through the upper optical module 202. In thisexample, the DLP mirrors are provided at 17 degrees to the surface ofthe DLP device. The angles of the TIR wedge are selected incorrespondence to one another to provide TIR reflected illuminationlight at the correct angle for the DLP mirrors while allowing the imagelight and dark state light to pass through the thin air gap, variouscombinations of angles are possible to achieve this.

FIG. 5 illustrates yet another embodiment of an upper optical module 202in accordance with the principles of the present invention. As with theembodiment shown in FIG. 4, the embodiment shown in FIG. 5 does notrequire the use of polarized light. Polarized light may be used inconnection with this embodiment, but it is not required. The opticalmodule 202 depicted in FIG. 5 is similar to that presented in connectionwith FIG. 4; however, the embodiment of FIG. 5 includes an off lightredirection wedge 502. As can be seen from the illustration, the offlight redirection wedge 502 allows the image light 414 to continuegenerally along the optical axis toward the field lens and into thelower optical module 204 (as illustrated). However, the off light 504 isredirected substantially toward the side of the corrective wedge 420where it passes into the light trap. This configuration may allowfurther height compactness in the HWC because the light trap (notillustrated) that is intended to absorb the off light 504 can bepositioned laterally adjacent the upper optical module 202 as opposed tobelow it. In the embodiment depicted in FIG. 5 there is a thin air gapbetween the TIR wedge 418 and the corrective wedge 420 (similar to theembodiment of FIG. 4). There is also a thin air gap between thecorrective wedge 420 and the off light redirection wedge 502. There maybe HWC mechanical configurations that warrant the positioning of a lighttrap for the dark state light elsewhere and the illustration depicted inFIG. 5 should be considered illustrative of the concept that the offlight can be redirected to create compactness of the overall HWC. FIG.5a illustrates an example of the embodiment described in connection withFIG. 5 with the addition of more details on the relative angles at thevarious surfaces and a light ray trace for image light and a light raytrace for dark light are shown as it passes through the upper opticalmodule 202. Again, various combinations of angles are possible.

FIG. 4b shows an illustration of a further embodiment in which a solidtransparent matched set of wedges 456 is provided with a reflectivepolarizer 450 at the interface between the wedges. Wherein the interfacebetween the wedges in the wedge set 456 is provided at an angle so thatillumination light 452 from the polarized light source 458 is reflectedat the proper angle (e.g. 34 degrees for a 17 degree DLP mirror) for theDLP mirror “on” state so that the reflected image light 414 is providedalong the optical axis of the field lens. The general geometry of thewedges in the wedge set 456 is similar to that shown in FIGS. 4 and 4 a.A quarter wave film 454 is provided on the DLP 402 surface so that theillumination light 452 is one polarization state (e.g. S polarizationstate) while in passing through the quarter wave film 454, reflectingfrom the DLP mirror and passing back through the quarter wave film 454,the image light 414 is converted to the other polarization state (e.g. Ppolarization state). The reflective polarizer is oriented such that theillumination light 452 with it's polarization state is reflected and theimage light 414 with it's other polarization state is transmitted. Sincethe dark state light from the “off” pixels 410 also passes through thequarter wave film 454 twice, it is also the other polarization state(e.g. P polarization state) so that it is transmitted by the reflectivepolarizer 450.

The angles of the faces of the wedge set 450 correspond to the neededangles to provide illumination light 452 at the angle needed by the DLPmirrors when in the “on” state so that the reflected image light 414 isreflected from the DLP along the optical axis of the field lens. Thewedge set 456 provides an interior interface where a reflectivepolarizer film can be located to redirect the illumination light 452toward the mirrors of the DLP 402. The wedge set also provides a matchedwedge on the opposite side of the reflective polarizer 450 so that theimage light 414 from the “on” pixels exits the wedge set 450substantially perpendicular to the exit surface, while the dark statelight from the ‘off’ pixels 410 exits at an oblique angle to the exitsurface. As a result, the image light 414 is substantially unrefractedupon exiting the wedge set 456, while the dark state light from the“off” pixels 410 is substantially refracted upon exiting the wedge set456 as shown in FIG. 4 b.

By providing a solid transparent matched wedge set, the flatness of theinterface is reduced, because variations in the flatness have anegligible effect as long as they are within the cone angle of theilluminating light 452. Which can be f#2.2 with a 26 degree cone angle.In a preferred embodiment, the reflective polarizer is bonded betweenthe matched internal surfaces of the wedge set 456 using an opticaladhesive so that Fresnel reflections at the interfaces on either side ofthe reflective polarizer 450 are reduced. The optical adhesive can bematched in refractive index to the material of the wedge set 456 and thepieces of the wedge set 456 can be all made from the same material suchas BK7 glass or cast acrylic. Wherein the wedge material can be selectedto have low birefringence as well to reduce non-uniformities inbrightness. The wedge set 456 and the quarter wave film 454 can also bebonded to the DLP 402 to further reduce Fresnel reflections at the DLPinterface losses. In addition, since the image light 414 issubstantially normal to the exit surface of the wedge set 456, theflatness of the surface is not critical to maintain the wavefront of theimage light 414 so that high image quality can be obtained in thedisplayed image without requiring very tightly toleranced flatness onthe exit surface.

A yet further embodiment of the invention that is not illustrated,combines the embodiments illustrated in FIG. 4b and FIG. 5. In thisembodiment, the wedge set 456 is comprised of three wedges with thegeneral geometry of the wedges in the wedge set corresponding to thatshown in FIGS. 5 and 5 a. A reflective polarizer is bonded between thefirst and second wedges similar to that shown in FIG. 4b , however, athird wedge is provided similar to the embodiment of FIG. 5. Whereinthere is an angled thin air gap between the second and third wedges sothat the dark state light is reflected by TIR toward the side of thesecond wedge where it is absorbed in a light trap. This embodiment, likethe embodiment shown in FIG. 4b , uses a polarized light source as hasbeen previously described. The difference in this embodiment is that theimage light is transmitted through the reflective polarizer and istransmitted through the angled thin air gap so that it exits normal tothe exit surface of the third wedge.

FIG. 5b illustrates an upper optical module 202 with a dark light trap514 a. As described in connection with FIGS. 4 and 4 a, image light canbe generated from a DLP when using a TIR and corrective lensconfiguration. The upper module may be mounted in a HWC housing 510 andthe housing 510 may include a dark light trap 514 a. The dark light trap514 a is generally positioned/constructed/formed in a position that isoptically aligned with the dark light optical axis 512. As illustrated,the dark light trap may have depth such that the trap internallyreflects dark light in an attempt to further absorb the light andprevent the dark light from combining with the image light that passesthrough the field lens. The dark light trap may be of a shape and depthsuch that it absorbs the dark light. In addition, the dark light trap514 b, in embodiments, may be made of light absorbing materials orcoated with light absorbing materials. In embodiments, the recessedlight trap 514 a may include baffles to block a view of the dark statelight. This may be combined with black surfaces and textured or fiberoussurfaces to help absorb the light. The baffles can be part of the lighttrap, associated with the housing, or field lens, etc.

FIG. 5c illustrates another embodiment with a light trap 514 b. As canbe seen in the illustration, the shape of the trap is configured toenhance internal reflections within the light trap 514 b to increase theabsorption of the dark light 512. FIG. 5d illustrates another embodimentwith a light trap 514 c. As can be seen in the illustration, the shapeof the trap 514 c is configured to enhance internal reflections toincrease the absorption of the dark light 512.

FIG. 5e illustrates another embodiment of an upper optical module 202with a dark light trap 514 d. This embodiment of upper module 202includes an off light reflection wedge 502, as illustrated and describedin connection with the embodiment of FIGS. 5 and 5 a. As can be seen inFIG. 5e , the light trap 514 d is positioned along the optical path ofthe dark light 512. The dark light trap 514 d may be configured asdescribed in other embodiments herein. The embodiment of the light trap514 d illustrated in FIG. 5e includes a black area on the side wall ofthe wedge, wherein the side wall is located substantially away from theoptical axis of the image light 414. In addition, baffles 5252 may beadded to one or more edges of the field lens 312 to block the view ofthe light trap 514 d adjacent to the displayed image seen by the user.

FIG. 6 illustrates a combination of an upper optical module 202 with alower optical module 204. In this embodiment, the image light projectedfrom the upper optical module 202 may or may not be polarized. The imagelight is reflected off a flat combiner element 602 such that it isdirected towards the user's eye. Wherein, the combiner element 602 is apartial mirror that reflects image light while transmitting asubstantial portion of light from the environment so the user can lookthrough the combiner element and see the environment surrounding theHWC.

The combiner 602 may include a holographic pattern, to form aholographic mirror. If a monochrome image is desired, there may be asingle wavelength reflection design for the holographic pattern on thesurface of the combiner 602. If the intention is to have multiple colorsreflected from the surface of the combiner 602, a multiple wavelengthholographic mirror may be included on the combiner surface. For example,in a three-color embodiment, where red, green and blue pixels aregenerated in the image light, the holographic mirror may be reflectiveto wavelengths substantially matching the wavelengths of the red, greenand blue light provided by the light source. This configuration can beused as a wavelength specific mirror where pre-determined wavelengths oflight from the image light are reflected to the user's eye. Thisconfiguration may also be made such that substantially all otherwavelengths in the visible pass through the combiner element 602 so theuser has a substantially clear view of the surroundings when lookingthrough the combiner element 602. The transparency between the user'seye and the surrounding may be approximately 80% when using a combinerthat is a holographic mirror. Wherein holographic mirrors can be madeusing lasers to produce interference patterns in the holographicmaterial of the combiner where the wavelengths of the lasers correspondto the wavelengths of light that are subsequently reflected by theholographic mirror.

In another embodiment, the combiner element 602 may include a notchmirror comprised of a multilayer coated substrate wherein the coating isdesigned to substantially reflect the wavelengths of light provided bythe light source and substantially transmit the remaining wavelengths inthe visible spectrum. For example, in the case where red, green and bluelight is provided by the light source to enable full color images to beprovided to the user, the notch mirror is a tristimulus notch mirrorwherein the multilayer coating is designed to reflect narrow bands ofred, green and blue light that are matched to the what is provided bythe light source and the remaining visible wavelengths are transmittedthrough the coating to enable a view of the environment through thecombiner. In another example where monochrome images are provided to theuser, the notch mirror is designed to reflect a single narrow band oflight that is matched to the wavelength range of the light provided bythe light source while transmitting the remaining visible wavelengths toenable a see-thru view of the environment. The combiner 602 with thenotch mirror would operate, from the user's perspective, in a mannersimilar to the combiner that includes a holographic pattern on thecombiner element 602. The combiner, with the tristimulus notch mirror,would reflect the “on” pixels to the eye because of the match betweenthe reflective wavelengths of the notch mirror and the color of theimage light, and the wearer would be able to see with high clarity thesurroundings. The transparency between the user's eye and thesurrounding may be approximately 80% when using the tristimulus notchmirror. In addition, the image provided by the upper optical module 202with the notch mirror combiner can provide higher contrast images thanthe holographic mirror combiner due to less scattering of the imaginglight by the combiner.

Light can escape through the combiner 602 and may produce face glow asthe light is generally directed downward onto the cheek of the user.When using a holographic mirror combiner or a tristimulus notch mirrorcombiner, the escaping light can be trapped to avoid face glow. Inembodiments, if the image light is polarized before the combiner, alinear polarizer can be laminated, or otherwise associated, to thecombiner, with the transmission axis of the polarizer oriented relativeto the polarized image light so that any escaping image light isabsorbed by the polarizer. In embodiments, the image light would bepolarized to provide S polarized light to the combiner for betterreflection. As a result, the linear polarizer on the combiner would beoriented to absorb S polarized light and pass P polarized light. Thisprovides the preferred orientation of polarized sunglasses as well.

If the image light is unpolarized, a microlouvered film such as aprivacy filter can be used to absorb the escaping image light whileproviding the user with a see-thru view of the environment. In thiscase, the absorbance or transmittance of the microlouvered film isdependent on the angle of the light. Where steep angle light is absorbedand light at less of an angle is transmitted. For this reason, in anembodiment, the combiner with the microlouver film is angled at greaterthan 45 degrees to the optical axis of the image light (e.g. thecombiner can be oriented at 50 degrees so the image light from the filelens is incident on the combiner at an oblique angle.

FIG. 7 illustrates an embodiment of a combiner element 602 at variousangles when the combiner element 602 includes a holographic mirror.Normally, a mirrored surface reflects light at an angle equal to theangle that the light is incident to the mirrored surface. Typically,this necessitates that the combiner element be at 45 degrees, 602 a, ifthe light is presented vertically to the combiner so the light can bereflected horizontally towards the wearer's eye. In embodiments, theincident light can be presented at angles other than vertical to enablethe mirror surface to be oriented at other than 45 degrees, but in allcases wherein a mirrored surface is employed (including the tristimulusnotch mirror described previously), the incident angle equals thereflected angle. As a result, increasing the angle of the combiner 602 arequires that the incident image light be presented to the combiner 602a at a different angle which positions the upper optical module 202 tothe left of the combiner as shown in FIG. 7. In contrast, a holographicmirror combiner, included in embodiments, can be made such that light isreflected at a different angle from the angle that the light is incidentonto the holographic mirrored surface. This allows freedom to select theangle of the combiner element 602 b independent of the angle of theincident image light and the angle of the light reflected into thewearer's eye. In embodiments, the angle of the combiner element 602 b isgreater than 45 degrees (shown in FIG. 7) as this allows a morelaterally compact HWC design. The increased angle of the combinerelement 602 b decreases the front to back width of the lower opticalmodule 204 and may allow for a thinner HWC display (i.e. the furthestelement from the wearer's eye can be closer to the wearer's face).

FIG. 8 illustrates another embodiment of a lower optical module 204. Inthis embodiment, polarized image light provided by the upper opticalmodule 202, is directed into the lower optical module 204. The imagelight reflects off a polarized mirror 804 and is directed to a focusingpartially reflective mirror 802, which is adapted to reflect thepolarized light. An optical element such as a ¼ wave film locatedbetween the polarized mirror 804 and the partially reflective mirror802, is used to change the polarization state of the image light suchthat the light reflected by the partially reflective mirror 802 istransmitted by the polarized mirror 804 to present image light to theeye of the wearer. The user can also see through the polarized mirror804 and the partially reflective mirror 802 to see the surroundingenvironment. As a result, the user perceives a combined image comprisedof the displayed image light overlaid onto the see-thru view of theenvironment.

While many of the embodiments of the present invention have beenreferred to as upper and lower modules containing certain opticalcomponents, it should be understood that the image light and dark lightproduction and management functions described in connection with theupper module may be arranged to direct light in other directions (e.g.upward, sideward, etc.). In embodiments, it may be preferred to mountthe upper module 202 above the wearer's eye, in which case the imagelight would be directed downward. In other embodiments it may bepreferred to produce light from the side of the wearer's eye, or frombelow the wearer's eye. In addition, the lower optical module isgenerally configured to deliver the image light to the wearer's eye andallow the wearer to see through the lower optical module, which may beaccomplished through a variety of optical components.

FIG. 8a illustrates an embodiment of the present invention where theupper optical module 202 is arranged to direct image light into a TIRwaveguide 810. In this embodiment, the upper optical module 202 ispositioned above the wearer's eye 812 and the light is directedhorizontally into the TIR waveguide 810. The TIR waveguide is designedto internally reflect the image light in a series of downward TIRreflections until it reaches the portion in front of the wearer's eye,where the light passes out of the TIR waveguide 812 into the wearer'seye. In this embodiment, an outer shield 814 is positioned in front ofthe TIR waveguide 810.

FIG. 8b illustrates an embodiment of the present invention where theupper optical module 202 is arranged to direct image light into a TIRwaveguide 818. In this embodiment, the upper optical module 202 isarranged on the side of the TIR waveguide 818. For example, the upperoptical module may be positioned in the arm or near the arm of the HWCwhen configured as a pair of head worn glasses. The TIR waveguide 818 isdesigned to internally reflect the image light in a series of TIRreflections until it reaches the portion in front of the wearer's eye,where the light passes out of the TIR waveguide 812 into the wearer'seye.

FIG. 8c illustrates yet further embodiments of the present inventionwhere an upper optical module 202 is directing polarized image lightinto an optical guide 828 where the image light passes through apolarized reflector 824, changes polarization state upon reflection ofthe optical element 822 which includes a ¼ wave film for example andthen is reflected by the polarized reflector 824 towards the wearer'seye, due to the change in polarization of the image light. The upperoptical module 202 may be positioned to direct light to a mirror 820, toposition the upper optical module 202 laterally, in other embodiments,the upper optical module 202 may direct the image light directly towardsthe polarized reflector 824. It should be understood that the presentinvention comprises other optical arrangements intended to direct imagelight into the wearer's eye.

Another aspect of the present invention relates to eye imaging. Inembodiments, a camera is used in connection with an upper optical module202 such that the wearer's eye can be imaged using pixels in the “off”state on the DLP. FIG. 9 illustrates a system where the eye imagingcamera 802 is mounted and angled such that the field of view of the eyeimaging camera 802 is redirected toward the wearer's eye by the mirrorpixels of the DLP 402 that are in the “off” state. In this way, the eyeimaging camera 802 can be used to image the wearer's eye along the sameoptical axis as the displayed image that is presented to the wearer.Wherein, image light that is presented to the wearer's eye illuminatesthe wearer's eye so that the eye can be imaged by the eye imaging camera802. In the process, the light reflected by the eye passes back thoughthe optical train of the lower optical module 204 and a portion of theupper optical module to where the light is reflected by the “off” pixelsof the DLP 402 toward the eye imaging camera 802.

In embodiments, the eye imaging camera may image the wearer's eye at amoment in time where there are enough “off” pixels to achieve therequired eye image resolution. In another embodiment, the eye imagingcamera collects eye image information from “off” pixels over time andforms a time lapsed image. In another embodiment, a modified image ispresented to the user wherein enough “off” state pixels are includedthat the camera can obtain the desired resolution and brightness forimaging the wearer's eye and the eye image capture is synchronized withthe presentation of the modified image.

The eye imaging system may be used for security systems. The HWC may notallow access to the HWC or other system if the eye is not recognized(e.g. through eye characteristics including retina or irischaracteristics, etc.). The HWC may be used to provide constant securityaccess in some embodiments. For example, the eye security confirmationmay be a continuous, near-continuous, real-time, quasi real-time,periodic, etc. process so the wearer is effectively constantly beingverified as known. In embodiments, the HWC may be worn and eye securitytracked for access to other computer systems.

The eye imaging system may be used for control of the HWC. For example,a blink, wink, or particular eye movement may be used as a controlmechanism for a software application operating on the HWC or associateddevice.

The eye imaging system may be used in a process that determines how orwhen the HWC 102 delivers digitally displayed content to the wearer. Forexample, the eye imaging system may determine that the user is lookingin a direction and then HWC may change the resolution in an area of thedisplay or provide some content that is associated with something in theenvironment that the user may be looking at. Alternatively, the eyeimaging system may identify different user's and change the displayedcontent or enabled features provided to the user. User's may beidentified from a database of users eye characteristics either locatedon the HWC 102 or remotely located on the network 110 or on a server112. In addition, the HWC may identify a primary user or a group ofprimary users from eye characteristics wherein the primary user(s) areprovided with an enhanced set of features and all other user's areprovided with a different set of features. Thus in this use case, theHWC 102 uses identified eye characteristics to either enable features ornot and eye characteristics need only be analyzed in comparison to arelatively small database of individual eye characteristics.

FIG. 10 illustrates a light source that may be used in association withthe upper optics module 202 (e.g. polarized light source if the lightfrom the solid state light source is polarized such as polarized lightsource 302 and 458), and light source 404. In embodiments, to provide auniform surface of light 1008 to be directed into the upper opticalmodule 202 and towards the DLP of the upper optical module, eitherdirectly or indirectly, the solid state light source 1002 may beprojected into a backlighting optical system 1004. The solid state lightsource 1002 may be one or more LEDs, laser diodes, OLEDs. Inembodiments, the backlighting optical system 1004 includes an extendedsection with a length/distance ratio of greater than 3, wherein thelight undergoes multiple reflections from the sidewalls to mix ofhomogenize the light as supplied by the solid state light source 1002.The backlighting optical system 1004 can also include structures on thesurface opposite (on the left side as shown in FIG. 10) to where theuniform light 1008 exits the backlight 1004 to change the direction ofthe light toward the DLP 302 and the reflective polarizer 310 or the DLP402 and the TIR wedge 418. The backlighting optical system 1004 may alsoinclude structures to collimate the uniform light 1008 to provide lightto the DLP with a smaller angular distribution or narrower cone angle.Diffusers or polarizers can be used on the entrance or exit surface ofthe backlighting optical system. Diffusers can be used to spread oruniformize the exiting light from the backlight to improve theuniformity or increase the angular spread of the uniform light 1008.Elliptical diffusers that diffuse the light more in some directions andless in others can be used to improve the uniformity or spread of theuniform light 1008 in directions orthogonal to the optical axis of theuniform light 1008. Linear polarizers can be used to convert unpolarizedlight as supplied by the solid state light source 1002 to polarizedlight so the uniform light 1008 is polarized with a desired polarizationstate. A reflective polarizer can be used on the exit surface of thebacklight 1004 to polarize the uniform light 1008 to the desiredpolarization state, while reflecting the other polarization state backinto the backlight where it is recycled by multiple reflections withinthe backlight 1004 and at the solid state light source 1002. Thereforeby including a reflective polarizer at the exit surface of the backlight1004, the efficiency of the polarized light source is improved.

FIGS. 10a and 10b show illustrations of structures in backlight opticalsystems 1004 that can be used to change the direction of the lightprovided to the entrance face 1045 by the light source and thencollimates the light in a direction lateral to the optical axis of theexiting uniform light 1008. Structure 1060 includes an angled sawtoothpattern in a transparent waveguide wherein the left edge of eachsawtooth clips the steep angle rays of light thereby limiting the angleof the light being redirected. The steep surface at the right (as shown)of each sawtooth then redirects the light so that it reflects off theleft angled surface of each sawtooth and is directed toward the exitsurface 1040. The sawtooth surfaces shown on the lower surface in FIGS.10a and 10b , can be smooth and coated (e.g. with an aluminum coating ora dielectric mirror coating) to provide a high level of reflectivitywithout scattering. Structure 1050 includes a curved face on the leftside (as shown) to focus the rays after they pass through the exitsurface 1040, thereby providing a mechanism for collimating the uniformlight 1008. In a further embodiment, a diffuser can be provided betweenthe solid state light source 1002 and the entrance face 1045 tohomogenize the light provided by the solid state light source 1002. Inyet a further embodiment, a polarizer can be used between the diffuserand the entrance face 1045 of the backlight 1004 to provide a polarizedlight source. Because the sawtooth pattern provides smooth reflectivesurfaces, the polarization state of the light can be preserved from theentrance face 1045 to the exit face 1040. In this embodiment, the lightentering the backlight from the solid state light source 1002 passesthrough the polarizer so that it is polarized with the desiredpolarization state. If the polarizer is an absorptive linear polarizer,the light of the desired polarization state is transmitted while thelight of the other polarization state is absorbed. If the polarizer is areflective polarizer, the light of the desired polarization state istransmitted into the backlight 1004 while the light of the otherpolarization state is reflected back into the solid state light source1002 where it can be recycled as previously described, to increase theefficiency of the polarized light source.

FIG. 11a illustrates a light source 1100 that may be used in associationwith the upper optics module 202. In embodiments, the light source 1100may provide light to a backlighting optical system 1004 as describedabove in connection with FIG. 10. In embodiments, the light source 1100includes a tristimulus notch filter 1102. The tristimulus notch filter1102 has narrow band pass filters for three wavelengths, as indicated inFIG. 11c in a transmission graph 1108. The graph shown in FIG. 11b , as1104 illustrates an output of three different colored LEDs. One can seethat the bandwidths of emission are narrow, but they have long tails.The tristimulus notch filter 1102 can be used in connection with suchLEDs to provide a light source 1100 that emits narrow filteredwavelengths of light as shown in FIG. 11d as the transmission graph1110. Wherein the clipping effects of the tristimulus notch filter 1102can be seen to have cut the tails from the LED emission graph 1104 toprovide narrower wavelength bands of light to the upper optical module202. The light source 1100 can be used in connection with a combiner 602with a holographic mirror or tristimulus notch mirror to provide narrowbands of light that are reflected toward the wearer's eye with lesswaste light that does not get reflected by the combiner, therebyimproving efficiency and reducing escaping light that can causefaceglow.

FIG. 12a illustrates another light source 1200 that may be used inassociation with the upper optics module 202. In embodiments, the lightsource 1200 may provide light to a backlighting optical system 1004 asdescribed above in connection with FIG. 10. In embodiments, the lightsource 1200 includes a quantum dot cover glass 1202. Where the quantumdots absorb light of a shorter wavelength and emit light of a longerwavelength (FIG. 12b shows an example wherein a UV spectrum 1202 appliedto a quantum dot results in the quantum dot emitting a narrow band shownas a PL spectrum 1204) that is dependent on the material makeup and sizeof the quantum dot. As a result, quantum dots in the quantum dot coverglass 1202 can be tailored to provide one or more bands of narrowbandwidth light (e.g. red, green and blue emissions dependent on thedifferent quantum dots included as illustrated in the graph shown inFIG. 12c where three different quantum dots are used. In embodiments,the LED driver light emits UV light, deep blue or blue light. Forsequential illumination of different colors, multiple light sources 1200would be used where each light source 1200 would include a quantum dotcover glass 1202 with a quantum dot selected to emit at one of thedesired colors. The light source 1100 can be used in connection with acombiner 602 with a holographic mirror or tristimulus notch mirror toprovide narrow transmission bands of light that are reflected toward thewearer's eye with less waste light that does not get reflected.

Another aspect of the present invention relates to the generation ofperipheral image lighting effects for a person wearing a HWC. Inembodiments, a solid state lighting system (e.g. LED, OLED, etc), orother lighting system, may be included inside the optical elements of anlower optical module 204. The solid state lighting system may bearranged such that lighting effects outside of a field of view (FOV) ofthe presented digital content is presented to create an emersive effectfor the person wearing the HWC. To this end, the lighting effects may bepresented to any portion of the HWC that is visible to the wearer. Thesolid state lighting system may be digitally controlled by an integratedprocessor on the HWC. In embodiments, the integrated processor willcontrol the lighting effects in coordination with digital content thatis presented within the FOV of the HWC. For example, a movie, picture,game, or other content, may be displayed or playing within the FOV ofthe HWC. The content may show a bomb blast on the right side of the FOVand at the same moment, the solid state lighting system inside of theupper module optics may flash quickly in concert with the FOV imageeffect. The effect may not be fast, it may be more persistent toindicate, for example, a general glow or color on one side of the user.The solid state lighting system may be color controlled, with red, greenand blue LEDs, for example, such that color control can be coordinatedwith the digitally presented content within the field of view.

FIG. 13a illustrates optical components of a lower optical module 204together with an outer lens 1302. FIG. 13a also shows an embodimentincluding effects LED's 1308 a and 1308 b. FIG. 13a illustrates imagelight 1312, as described herein elsewhere, directed into the upperoptical module where it will reflect off of the combiner element 1304,as described herein elsewhere. The combiner element 1304 in thisembodiment is angled towards the wearer's eye at the top of the moduleand away from the wearer's eye at the bottom of the module, as alsoillustrated and described in connection with FIG. 8 (e.g. at a 45 degreeangle). The image light 1312 provided by an upper optical module 202(not shown in FIG. 13a ) reflects off of the combiner element 1304towards the collimating mirror 1310, away from the wearer's eye, asdescribed herein elsewhere. The image light 1312 then reflects andfocuses off of the collimating mirror 1304, passes back through thecombiner element 1304, and is directed into the wearer's eye. The wearercan also view the surrounding environment through the transparency ofthe combiner element 1304, collimating mirror 1310, and outer lens 1302(if it is included). As described herein elsewhere, various surfaces arepolarized to create the optical path for the image light and to providetransparency of the elements such that the wearer can view thesurrounding environment. The wearer will generally perceive that theimage light forms an image in the FOV 1305. In embodiments, the outerlens 1302 may be included. The outer lens 1302 is an outer lens that mayor may not be corrective and it may be designed to conceal the loweroptical module components in an effort to make the HWC appear to be in aform similar to standard glasses or sunglasses.

In the embodiment illustrated in FIG. 13a , the effects LEDs 1308 a and1308 b are positioned at the sides of the combiner element 1304 and theouter lens 1302 and/or the collimating mirror 1310. In embodiments, theeffects LEDs 1308 a are positioned within the confines defined by thecombiner element 1304 and the outer lens 1302 and/or the collimatingmirror. The effects LEDs 1308 a and 1308 b are also positioned outsideof the FOV 1305. In this arrangement, the effects LEDs 1308 a and 1308 bcan provide lighting effects within the lower optical module outside ofthe FOV 1305. In embodiments the light emitted from the effects LEDs1308 a and 1308 b may be polarized such that the light passes throughthe combiner element 1304 toward the wearer's eye and does not passthrough the outer lens 1302 and/or the collimating mirror 1310. Thisarrangement provides peripheral lighting effects to the wearer in a moreprivate setting by not transmitting the lighting effects through thefront of the HWC into the surrounding environment. However, in otherembodiments, the effects LEDs 1308 a and 1308 b may be unpolarized sothe lighting effects provided are made to be purposefully viewable byothers in the environment for entertainment such as giving the effect ofthe wearer's eye glowing in correspondence to the image content beingviewed by the wearer.

FIG. 13b illustrates a cross section of the embodiment described inconnection with FIG. 13a . As illustrated, the effects LED 1308 a islocated in the upper-front area inside of the optical components of thelower optical module. It should be understood that the effects LED 1308a position in the described embodiments is only illustrative andalternate placements are encompassed by the present invention.Additionally, in embodiments, there may be one or more effects LEDs 1308a in each of the two sides of HWC to provide peripheral lighting effectsnear one or both eyes of the wearer.

FIG. 13c illustrates an embodiment where the combiner element 1304 isangled away from the eye at the top and towards the eye at the bottom(e.g. in accordance with the holographic or notch filter embodimentsdescribed herein). In this embodiment, the effects LED 1308 a is locatedon the outer lens 1302 side of the combiner element 1304 to provide aconcealed appearance of the lighting effects. As with other embodiments,the effects LED 1308 a of FIG. 13c may include a polarizer such that theemitted light can pass through a polarized element associated with thecombiner element 1304 and be blocked by a polarized element associatedwith the outer lens 1302.

Another aspect of the present invention relates to the mitigation oflight escaping from the space between the wearer's face and the HWCitself. Another aspect of the present invention relates to maintaining acontrolled lighting environment in proximity to the wearer's eyes. Inembodiments, both the maintenance of the lighting environment and themitigation of light escape are accomplished by including a removable andreplaceable flexible shield for the HWC. Wherein the removable andreplaceable shield can be provided for one eye or both eyes incorrespondence to the use of the displays for each eye. For example, ina night vision application, the display to only one eye could be usedfor night vision while the display to the other eye is turned off toprovide good see-thru when moving between areas where visible light isavailable and dark areas where night vision enhancement is needed.

FIG. 14a illustrates a removable and replaceable flexible eye cover 1402with an opening 1408 that can be attached and removed quickly from theHWC 102 through the use of magnets. Other attachment methods may beused, but for illustration of the present invention we will focus on amagnet implementation. In embodiments, magnets may be included in theeye cover 1402 and magnets of an opposite polarity may be included (e.g.embedded) in the frame of the HWC 102. The magnets of the two elementswould attract quite strongly with the opposite polarity configuration.In another embodiment, one of the elements may have a magnet and theother side may have metal for the attraction. In embodiments, the eyecover 1402 is a flexible elastomeric shield. In embodiments, the eyecover 1402 may be an elastomeric bellows design to accommodateflexibility and more closely align with the wearer's face. FIG. 14billustrates a removable and replaceable flexible eye cover 1404 that isadapted as a single eye cover. In embodiments, a single eye cover may beused for each side of the HWC to cover both eyes of the wearer. Inembodiments, the single eye cover may be used in connection with a HWCthat includes only one computer display for one eye. Theseconfigurations prevent light that is generated and directed generallytowards the wearer's face by covering the space between the wearer'sface and the HWC. The opening 1408 allows the wearer to look through theopening 1408 to view the displayed content and the surroundingenvironment through the front of the HWC. The image light in the loweroptical module 204 can be prevented from emitting from the front of theHWC through internal optics polarization schemes, as described herein,for example.

FIG. 14c illustrates another embodiment of a light suppression system.In this embodiment, the eye cover 1410 may be similar to the eye cover1402, but eye cover 1410 includes a front light shield 1412. The frontlight shield 1412 may be opaque to prevent light from escaping the frontlens of the HWC. In other embodiments, the front light shield 1412 ispolarized to prevent light from escaping the front lens. In a polarizedarrangement, in embodiments, the internal optical elements of the HWC(e.g. of the lower optical module 204) may polarize light transmittedtowards the front of the HWC and the front light shield 1412 may bepolarized to prevent the light from transmitting through the front lightshield 1412.

In embodiments, an opaque front light shield 1412 may be included andthe digital content may include images of the surrounding environmentsuch that the wearer can visualize the surrounding environment. One eyemay be presented with night vision environmental imagery and this eye'ssurrounding environment optical path may be covered using an opaquefront light shield 1412. In other embodiments, this arrangement may beassociated with both eyes.

Another aspect of the present invention relates to automaticallyconfiguring the lighting system(s) used in the HWC 102. In embodiments,the display lighting and/or effects lighting, as described herein, maybe controlled in a manner suitable for when an eye cover 1408 isattached or removed from the HWC 102. For example, at night, when thelight in the environment is low, the lighting system(s) in the HWC maygo into a low light mode to further control any amounts of stray lightescaping from the HWC and the areas around the HWC. Covert operations atnight, while using night vision or standard vision, may require asolution which prevents as much escaping light as possible so a user mayclip on the eye cover(s) 1408 and then the HWC may go into a low lightmode. The low light mode may, in some embodiments, only go into a lowlight mode when the eye cover 1408 is attached if the HWC identifiesthat the environment is in low light conditions (e.g. throughenvironment light level sensor detection). In embodiments, the low lightlevel may be determined to be at an intermediate point between full andlow light dependent on environmental conditions.

Another aspect of the present invention relates to automaticallycontrolling the type of content displayed in the HWC when eye covers1408 are attached or removed from the HWC. In embodiments, when the eyecover(s) 1408 is attached to the HWC, the displayed content may berestricted in amount or in color amounts. For example, the display(s)may go into a simple content delivery mode to restrict the amount ofinformation displayed. This may be done to reduce the amount of lightproduced by the display(s). In an embodiment, the display(s) may changefrom color displays to monochrome displays to reduce the amount of lightproduced. In an embodiment, the monochrome lighting may be red to limitthe impact on the wearer's eyes to maintain an ability to see better inthe dark.

Referring to FIG. 15, we now turn to describe a particular external userinterface 104, referred to generally as a pen 1500. The pen 1500 is aspecially designed external user interface 104 and can operate as a userinterface, such as to many different styles of HWC 102. The pen 1500generally follows the form of a conventional pen, which is a familiaruser handled device and creates an intuitive physical interface for manyof the operations to be carried out in the HWC system 100. The pen 1500may be one of several user interfaces 104 used in connection withcontrolling operations within the HWC system 100. For example, the HWC102 may watch for and interpret hand gestures 116 as control signals,where the pen 1500 may also be used as a user interface with the sameHWC 102. Similarly, a remote keyboard may be used as an external userinterface 104 in concert with the pen 1500. The combination of userinterfaces or the use of just one control system generally depends onthe operation(s) being executed in the HWC's system 100.

While the pen 1500 may follow the general form of a conventional pen, itcontains numerous technologies that enable it to function as an externaluser interface 104. FIG. 15 illustrates technologies comprised in thepen 1500. As can be seen, the pen 1500 may include a camera 1508, whichis arranged to view through lens 1502. The camera may then be focused,such as through lens 1502, to image a surface upon which a user iswriting or making other movements to interact with the HWC 102. Thereare situations where the pen 1500 will also have an ink, graphite, orother system such that what is being written can be seen on the writingsurface. There are other situations where the pen 1500 does not havesuch a physical writing system so there is no deposit on the writingsurface, where the pen would only be communicating data or commands tothe HWC 102. The lens configuration is described in greater detailherein. The function of the camera is to capture information from anunstructured writing surface such that pen strokes can be interpreted asintended by the user. To assist in the predication of the intendedstroke path, the pen 1500 may include a sensor, such as an IMU 1512. Ofcourse, the IMU could be included in the pen 1500 in its separate parts(e.g. gyro, accelerometer, etc.) or an IMU could be included as a singleunit. In this instance, the IMU 1512 is used to measure and predict themotion of the pen 1500. In turn, the integrated microprocessor 1510would take the IMU information and camera information as inputs andprocess the information to form a prediction of the pen tip movement.

The pen 1500 may also include a pressure monitoring system 1504, such asto measure the pressure exerted on the lens 1502. As will be describedin greater detail herein, the pressure measurement can be used topredict the user's intention for changing the weight of a line, type ofa line, type of brush, click, double click, and the like. Inembodiments, the pressure sensor may be constructed using any force orpressure measurement sensor located behind the lens 1502, including forexample, a resistive sensor, a current sensor, a capacitive sensor, avoltage sensor such as a piezoelectric sensor, and the like.

The pen 1500 may also include a communications module 1518, such as forbi-directional communication with the HWC 102. In embodiments, thecommunications module 1518 may be a short distance communication module(e.g. Bluetooth). The communications module 1518 may be security matchedto the HWC 102. The communications module 1518 may be arranged tocommunicate data and commands to and from the microprocessor 1510 of thepen 1500. The microprocessor 1510 may be programmed to interpret datagenerated from the camera 1508, IMU 1512, and pressure sensor 1504, andthe like, and then pass a command onto the HWC 102 through thecommunications module 1518, for example. In another embodiment, the datacollected from any of the input sources (e.g. camera 1508, IMU 1512,pressure sensor 1504) by the microprocessor may be communicated by thecommunication module 1518 to the HWC 102, and the HWC 102 may performdata processing and prediction of the user's intention when using thepen 1500. In yet another embodiment, the data may be further passed onthrough a network 110 to a remote device 112, such as a server, for thedata processing and prediction. The commands may then be communicatedback to the HWC 102 for execution (e.g. display writing in the glassesdisplay, make a selection within the UI of the glasses display, controla remote external device 112, control a local external device 108), andthe like. The pen may also include memory 1514 for long or short termuses.

The pen 1500 may also include a number of physical user interfaces, suchas quick launch buttons 1522, a touch sensor 1520, and the like. Thequick launch buttons 1522 may be adapted to provide the user with a fastway of jumping to a software application in the HWC system 100. Forexample, the user may be a frequent user of communication softwarepackages (e.g. email, text, Twitter, Instagram, Facebook, Google+, andthe like), and the user may program a quick launch button 1522 tocommand the HWC 102 to launch an application. The pen 1500 may beprovided with several quick launch buttons 1522, which may be userprogrammable or factory programmable. The quick launch button 1522 maybe programmed to perform an operation. For example, one of the buttonsmay be programmed to clear the digital display of the HWC 102. Thiswould create a fast way for the user to clear the screens on the HWC 102for any reason, such as for example to better view the environment. Thequick launch button functionality will be discussed in further detailbelow. The touch sensor 1520 may be used to take gesture style inputfrom the user. For example, the user may be able to take a single fingerand run it across the touch sensor 1520 to affect a page scroll.

The pen 1500 may also include a laser pointer 1524. The laser pointer1524 may be coordinated with the IMU 1512 to coordinate gestures andlaser pointing. For example, a user may use the laser 1524 in apresentation to help with guiding the audience with the interpretationof graphics and the IMU 1512 may, either simultaneously or when thelaser 1524 is off, interpret the user's gestures as commands or datainput.

FIGS. 16A-C illustrate several embodiments of lens and cameraarrangements 1600 for the pen 1500. One aspect relates to maintaining aconstant distance between the camera and the writing surface to enablethe writing surface to be kept in focus for better tracking of movementsof the pen 1500 over the writing surface. Another aspect relates tomaintaining an angled surface following the circumference of the writingtip of the pen 1500 such that the pen 1500 can be rolled or partiallyrolled in the user's hand to create the feel and freedom of aconventional writing instrument.

FIG. 16A illustrates an embodiment of the writing lens end of the pen1500. The configuration includes a ball lens 1604, a camera or imagecapture surface 1602, and a domed cover lens 1608. In this arrangement,the camera views the writing surface through the ball lens 1604 and domecover lens 1608. The ball lens 1604 causes the camera to focus such thatthe camera views the writing surface when the pen 1500 is held in thehand in a natural writing position, such as with the pen 1500 in contactwith a writing surface. In embodiments, the ball lens 1604 should beseparated from the writing surface to obtain the highest resolution ofthe writing surface at the camera 1602. In embodiments, the ball lens1604 is separated by approximately 1 to 3 mm. In this configuration, thedomed cover lens 1608 provides a surface that can keep the ball lens1604 separated from the writing surface at a constant distance, such assubstantially independent of the angle used to write on the writingsurface. For instance, in embodiments the field of view of the camera inthis arrangement would be approximately 60 degrees.

The domed cover lens, or other lens 1608 used to physically interactwith the writing surface, will be transparent or transmissive within theactive bandwidth of the camera 1602. In embodiments, the domed coverlens 1608 may be spherical or other shape and comprised of glass,plastic, sapphire, diamond, and the like. In other embodiments where lowresolution imaging of the surface is acceptable. The pen 1500 can omitthe domed cover lens 1608 and the ball lens 1604 can be in directcontact with the surface.

FIG. 16B illustrates another structure where the construction issomewhat similar to that described in connection with FIG. 16A; howeverthis embodiment does not use a dome cover lens 1608, but instead uses aspacer 1610 to maintain a predictable distance between the ball lens1604 and the writing surface, wherein the spacer may be spherical,cylindrical, tubular or other shape that provides spacing while allowingfor an image to be obtained by the camera 1602 through the lens 1604. Ina preferred embodiment, the spacer 1610 is transparent. In addition,while the spacer 1610 is shown as spherical, other shapes such as anoval, doughnut shape, half sphere, cone, cylinder or other form may beused.

FIG. 16C illustrates yet another embodiment, where the structureincludes a post 1614, such as running through the center of the lensedend of the pen 1500. The post 1614 may be an ink deposition system (e.g.ink cartridge), graphite deposition system (e.g. graphite holder), or adummy post whose purpose is mainly only that of alignment. The selectionof the post type is dependent on the pen's use. For instance, in theevent the user wants to use the pen 1500 as a conventional inkdepositing pen as well as a fully functional external user interface104, the ink system post would be the best selection. If there is noneed for the ‘writing’ to be visible on the writing surface, theselection would be the dummy post. The embodiment of FIG. 16C includescamera(s) 1602 and an associated lens 1612, where the camera 1602 andlens 1612 are positioned to capture the writing surface withoutsubstantial interference from the post 1614. In embodiments, the pen1500 may include multiple cameras 1602 and lenses 1612 such that more orall of the circumference of the tip 1614 can be used as an input system.In an embodiment, the pen 1500 includes a contoured grip that keeps thepen aligned in the user's hand so that the camera 1602 and lens 1612remains pointed at the surface.

Another aspect of the pen 1500 relates to sensing the force applied bythe user to the writing surface with the pen 1500. The force measurementmay be used in a number of ways. For example, the force measurement maybe used as a discrete value, or discontinuous event tracking, andcompared against a threshold in a process to determine a user's intent.The user may want the force interpreted as a ‘click’ in the selection ofan object, for instance. The user may intend multiple force exertionsinterpreted as multiple clicks. There may be times when the user holdsthe pen 1500 in a certain position or holds a certain portion of the pen1500 (e.g. a button or touch pad) while clicking to affect a certainoperation (e.g. a ‘right click’). In embodiments, the force measurementmay be used to track force and force trends. The force trends may betracked and compared to threshold limits, for example. There may be onesuch threshold limit, multiple limits, groups of related limits, and thelike. For example, when the force measurement indicates a fairlyconstant force that generally falls within a range of related thresholdvalues, the microprocessor 1510 may interpret the force trend as anindication that the user desires to maintain the current writing style,writing tip type, line weight, brush type, and the like. In the eventthat the force trend appears to have gone outside of a set of thresholdvalues intentionally, the microprocessor may interpret the action as anindication that the user wants to change the current writing style,writing tip type, line weight, brush type, and the like. Once themicroprocessor has made a determination of the user's intent, a changein the current writing style, writing tip type, line weight, brush type,and the like may be executed. In embodiments, the change may be noted tothe user (e.g. in a display of the HWC 102), and the user may bepresented with an opportunity to accept the change.

FIG. 17A illustrates an embodiment of a force sensing surface tip 1700of a pen 1500. The force sensing surface tip 1700 comprises a surfaceconnection tip 1702 (e.g. a lens as described herein elsewhere) inconnection with a force or pressure monitoring system 1504. As a useruses the pen 1500 to write on a surface or simulate writing on a surfacethe force monitoring system 1504 measures the force or pressure the userapplies to the writing surface and the force monitoring systemcommunicates data to the microprocessor 1510 for processing. In thisconfiguration, the microprocessor 1510 receives force data from theforce monitoring system 1504 and processes the data to make predictionsof the user's intent in applying the particular force that is currentlybeing applied. In embodiments, the processing may be provided at alocation other than on the pen (e.g. at a server in the HWC system 100,on the HWC 102). For clarity, when reference is made herein toprocessing information on the microprocessor 1510, the processing ofinformation contemplates processing the information at a location otherthan on the pen. The microprocessor 1510 may be programmed with forcethreshold(s), force signature(s), force signature library and/or othercharacteristics intended to guide an inference program in determiningthe user's intentions based on the measured force or pressure. Themicroprocessor 1510 may be further programmed to make inferences fromthe force measurements as to whether the user has attempted to initiatea discrete action (e.g. a user interface selection ‘click’) or isperforming a constant action (e.g. writing within a particular writingstyle). The inferencing process is important as it causes the pen 1500to act as an intuitive external user interface 104.

FIG. 17B illustrates a force 1708 versus time 1710 trend chart with asingle threshold 1718. The threshold 1718 may be set at a level thatindicates a discrete force exertion indicative of a user's desire tocause an action (e.g. select an object in a GUI). Event 1712, forexample, may be interpreted as a click or selection command because theforce quickly increased from below the threshold 1718 to above thethreshold 1718. The event 1714 may be interpreted as a double clickbecause the force quickly increased above the threshold 1718, decreasedbelow the threshold 1718 and then essentially repeated quickly. The usermay also cause the force to go above the threshold 1718 and hold for aperiod indicating that the user is intending to select an object in theGUI (e.g. a GUI presented in the display of the HWC 102) and ‘hold’ fora further operation (e.g. moving the object).

While a threshold value may be used to assist in the interpretation ofthe user's intention, a signature force event trend may also be used.The threshold and signature may be used in combination or either methodmay be used alone. For example, a single-click signature may berepresented by a certain force trend signature or set of signatures. Thesingle-click signature(s) may require that the trend meet a criteria ofa rise time between x any y values, a hold time of between a and bvalues and a fall time of between c and d values, for example.Signatures may be stored for a variety of functions such as click,double click, right click, hold, move, etc. The microprocessor 1510 maycompare the real-time force or pressure tracking against the signaturesfrom a signature library to make a decision and issue a command to thesoftware application executing in the GUI.

FIG. 17C illustrates a force 1708 versus time 1710 trend chart withmultiple thresholds 1718. By way of example, the force trend is plottedon the chart with several pen force or pressure events. As noted, thereare both presumably intentional events 1720 and presumablynon-intentional events 1722. The two thresholds 1718 of FIG. 4C createthree zones of force: a lower, middle and higher range. The beginning ofthe trend indicates that the user is placing a lower zone amount offorce. This may mean that the user is writing with a given line weightand does not intend to change the weight, the user is writing. Then thetrend shows a significant increase 1720 in force into the middle forcerange. This force change appears, from the trend to have been sudden andthereafter it is sustained. The microprocessor 1510 may interpret thisas an intentional change and as a result change the operation inaccordance with preset rules (e.g. change line width, increase lineweight, etc.). The trend then continues with a second apparentlyintentional event 1720 into the higher-force range. During theperformance in the higher-force range, the force dips below the upperthreshold 1718. This may indicate an unintentional force change and themicroprocessor may detect the change in range however not affect achange in the operations being coordinated by the pen 1500. As indicatedabove, the trend analysis may be done with thresholds and/or signatures.

Generally, in the present disclosure, instrument stroke parameterchanges may be referred to as a change in line type, line weight, tiptype, brush type, brush width, brush pressure, color, and other forms ofwriting, coloring, painting, and the like.

Another aspect of the pen 1500 relates to selecting an operating modefor the pen 1500 dependent on contextual information and/or selectioninterface(s). The pen 1500 may have several operating modes. Forinstance, the pen 1500 may have a writing mode where the userinterface(s) of the pen 1500 (e.g. the writing surface end, quick launchbuttons 1522, touch sensor 1520, motion based gesture, and the like) isoptimized or selected for tasks associated with writing. As anotherexample, the pen 1500 may have a wand mode where the user interface(s)of the pen is optimized or selected for tasks associated with softwareor device control (e.g. the HWC 102, external local device, remotedevice 112, and the like). The pen 1500, by way of another example, mayhave a presentation mode where the user interface(s) is optimized orselected to assist a user with giving a presentation (e.g. pointing withthe laser pointer 1524 while using the button(s) 1522 and/or gestures tocontrol the presentation or applications relating to the presentation).The pen may, for example, have a mode that is optimized or selected fora particular device that a user is attempting to control. The pen 1500may have a number of other modes and an aspect of the present inventionrelates to selecting such modes.

FIG. 18A illustrates an automatic user interface(s) mode selection basedon contextual information. The microprocessor 1510 may be programmedwith IMU thresholds 1814 and 1812. The thresholds 1814 and 1812 may beused as indications of upper and lower bounds of an angle 1804 and 1802of the pen 1500 for certain expected positions during certain predictedmodes. When the microprocessor 1510 determines that the pen 1500 isbeing held or otherwise positioned within angles 1802 corresponding towriting thresholds 1814, for example, the microprocessor 1510 may theninstitute a writing mode for the pen's user interfaces. Similarly, ifthe microprocessor 1510 determines (e.g. through the IMU 1512) that thepen is being held at an angle 1804 that falls between the predeterminedwand thresholds 1812, the microprocessor may institute a wand mode forthe pen's user interface. Both of these examples may be referred to ascontext based user interface mode selection as the mode selection isbased on contextual information (e.g. position) collected automaticallyand then used through an automatic evaluation process to automaticallyselect the pen's user interface(s) mode.

As with other examples presented herein, the microprocessor 1510 maymonitor the contextual trend (e.g. the angle of the pen over time) in aneffort to decide whether to stay in a mode or change modes. For example,through signatures, thresholds, trend analysis, and the like, themicroprocessor may determine that a change is an unintentional changeand therefore no user interface mode change is desired.

FIG. 18B illustrates an automatic user interface(s) mode selection basedon contextual information. In this example, the pen 1500 is monitoring(e.g. through its microprocessor) whether or not the camera at thewriting surface end 1508 is imaging a writing surface in close proximityto the writing surface end of the pen 1500. If the pen 1500 determinesthat a writing surface is within a predetermined relatively shortdistance, the pen 1500 may decide that a writing surface is present 1820and the pen may go into a writing mode user interface(s) mode. In theevent that the pen 1500 does not detect a relatively close writingsurface 1822, the pen may predict that the pen is not currently beingused to as a writing instrument and the pen may go into a non-writinguser interface(s) mode.

FIG. 18C illustrates a manual user interface(s) mode selection. The userinterface(s) mode may be selected based on a twist of a section 1824 ofthe pen 1500 housing, clicking an end button 1828, pressing a quicklaunch button 1522, interacting with touch sensor 1520, detecting apredetermined action at the pressure monitoring system (e.g. a click),detecting a gesture (e.g. detected by the IMU), etc. The manual modeselection may involve selecting an item in a GUI associated with the pen1500 (e.g. an image presented in the display of HWC 102).

In embodiments, a confirmation selection may be presented to the user inthe event a mode is going to change. The presentation may be physical(e.g. a vibration in the pen 1500), through a GUI, through a lightindicator, etc.

FIG. 19 illustrates a couple pen use-scenarios 1900 and 1901. There aremany use scenarios and we have presented a couple in connection withFIG. 19 as a way of illustrating use scenarios to further theunderstanding of the reader. As such, the use-scenarios should beconsidered illustrative and non-limiting.

Use scenario 1900 is a writing scenario where the pen 1500 is used as awriting instrument. In this example, quick launch button 122A is pressedto launch a note application 1910 in the GUI 1908 of the HWC 102 display1904. Once the quick launch button 122A is pressed, the HWC 102 launchesthe note program 1910 and puts the pen into a writing mode. The useruses the pen 1500 to scribe symbols 1902 on a writing surface, the penrecords the scribing and transmits the scribing to the HWC 102 wheresymbols representing the scribing are displayed 1912 within the noteapplication 1910.

Use scenario 1901 is a gesture scenario where the pen 1500 is used as agesture capture and command device. In this example, the quick launchbutton 122B is activated and the pen 1500 activates a wand mode suchthat an application launched on the HWC 102 can be controlled. Here, theuser sees an application chooser 1918 in the display(s) of the HWC 102where different software applications can be chosen by the user. Theuser gestures (e.g. swipes, spins, turns, etc.) with the pen to causethe application chooser 1918 to move from application to application.Once the correct application is identified (e.g. highlighted) in thechooser 1918, the user may gesture or click or otherwise interact withthe pen 1500 such that the identified application is selected andlaunched. Once an application is launched, the wand mode may be used toscroll, rotate, change applications, select items, initiate processes,and the like, for example.

In an embodiment, the quick launch button 122A may be activated and theHWC 102 may launch an application chooser presenting to the user a setof applications. For example, the quick launch button may launch achooser to show all communication programs (e.g. SMS, Twitter,Instagram, Facebook, email, etc.) available for selection such that theuser can select the program the user wants and then go into a writingmode. By way of further example, the launcher may bring up selectionsfor various other groups that are related or categorized as generallybeing selected at a given time (e.g. Microsoft Office products,communication products, productivity products, note products,organizational products, and the like)

FIG. 20 illustrates yet another embodiment of the present invention.FIG. 2000 illustrates a watchband clip on controller 2000. The watchbandclip on controller may be a controller used to control the HWC 102 ordevices in the HWC system 100. The watchband clip on controller 2000 hasa fastener 2018 (e.g. rotatable clip) that is mechanically adapted toattach to a watchband, as illustrated at 2004.

The watchband controller 2000 may have quick launch interfaces 2008(e.g. to launch applications and choosers as described herein), a touchpad 2014 (e.g. to be used as a touch style mouse for GUI control in aHWC 102 display) and a display 2012. The clip 2018 may be adapted to fita wide range of watchbands so it can be used in connection with a watchthat is independently selected for its function. The clip, inembodiments, is rotatable such that a user can position it in adesirable manner. In embodiments the clip may be a flexible strap. Inembodiments, the flexible strap may be adapted to be stretched to attachto a hand, wrist, finger, device, weapon, and the like.

In embodiments, the watchband controller may be configured as aremovable and replacable watchband. For example, the controller may beincorporated into a band with a certain width, segment spacing's, etc.such that the watchband, with its incorporated controller, can beattached to a watch body. The attachment, in embodiments, may bemechanically adapted to attach with a pin upon which the watchbandrotates. In embodiments, the watchband controller may be electricallyconnected to the watch and/or watch body such that the watch, watch bodyand/or the watchband controller can communicate data between them.

The watchband controller may have 3-axis motion monitoring (e.g. throughan IMU, accelerometers, magnetometers, gyroscopes, etc.) to capture usermotion. The user motion may then be interpreted for gesture control.

In embodiments, the watchband controller may comprise fitness sensorsand a fitness computer. The sensors may track heart rate, caloriesburned, strides, distance covered, and the like. The data may then becompared against performance goals and/or standards for user feedback.

Another aspect of the present invention relates to visual displaytechniques relating to micro Doppler (“mD”) target tracking signatures(“mD signatures”). mD is a radar technique that uses a series of angledependent electromagnetic pulses that are broadcast into an environmentand return pulses are captured. Changes between the broadcast pulse andreturn pulse are indicative of changes in the shape, distance andangular location of objects or targets in the environment. These changesprovide signals that can be used to track a target and identify thetarget through the mD signature. Each target or target type has a uniquemD signature. Shifts in the radar pattern can be analyzed in the timedomain and frequency domain based on mD techniques to derive informationabout the types of targets present (e.g. whether people are present),the motion of the targets and the relative angular location of thetargets and the distance to the targets. By selecting a frequency usedfor the mD pulse relative to known objects in the environment, the pulsecan penetrate the known objects to enable information about targets tobe gathered even when the targets are visually blocked by the knownobjects. For example, pulse frequencies can be used that will penetrateconcrete buildings to enable people to be identified inside thebuilding. Multiple pulse frequencies can be used as well in the mD radarto enable different types of information to be gathered about theobjects in the environment. In addition, the mD radar information can becombined with other information such as distance measurements or imagescaptured of the environment that are analyzed jointly to provideimproved object identification and improved target identification andtracking. In embodiments, the analysis can be performed on the HWC orthe information can be transmitted to a remote network for analysis andresults transmitted back to the HWC. Distance measurements can beprovided by laser range finding, structured lighting, stereoscopic depthmaps or sonar measurements. Images of the environment can be capturedusing one or more cameras capable of capturing images from visible,ultraviolet or infrared light. The mD radar can be attached to the HWC,located adjacently (e.g. in a vehicle) and associated wirelessly withthe HWC or located remotely. Maps or other previously determinedinformation about the environment can also be used in the analysis ofthe mD radar information. Embodiments of the present invention relate tovisualizing the mD signatures in useful ways.

FIG. 21 illustrates a FOV 2102 of a HWC 102 from a wearer's perspective.The wearer, as described herein elsewhere, has a see-through FOV 2102wherein the wearer views adjacent surroundings, such as the buildingsillustrated in FIG. 21. The wearer, as described herein elsewhere, canalso see displayed digital content presented within a portion of the FOV2102. The embodiment illustrated in FIG. 21 is indicating that thewearer can see the buildings and other surrounding elements in theenvironment and digital content representing traces, or travel paths, ofbullets being fired by different people in the area. The surroundingsare viewed through the transparency of the FOV 2102. The traces arepresented via the digital computer display, as described hereinelsewhere. In embodiments, the trace presented is based on a mDsignature that is collected and communicated to the HWC in real time.The mD radar itself may be on or near the wearer of the HWC 102 or itmay be located remote from the wearer. In embodiments, the mD radarscans the area, tracks and identifies targets, such as bullets, andcommunicates traces, based on locations, to the HWC 102.

There are several traces 2108 and 2104 presented to the wearer in theembodiment illustrated in FIG. 21. The traces communicated from the mDradar may be associated with GPS locations and the GPS locations may beassociated with objects in the environment, such as people, buildings,vehicles, etc, both in latitude and longitude perspective and anelevation perspective. The locations may be used as markers for the HWCsuch that the traces, as presented in the FOV, can be associated, orfixed in space relative to the markers. For example, if the friendlyfire trace 2108 is determined, by the mD radar, to have originated fromthe upper right window of the building on the left, as illustrated inFIG. 21, then a virtual marker may be set on or near the window. Whenthe HWC views, through it's camera or other sensor, for example, thebuilding's window, the trace may then virtually anchor with the virtualmarker on the window. Similarly, a marker may be set near thetermination position or other flight position of the friendly fire trace2108, such as the upper left window of the center building on the right,as illustrated in FIG. 21. This technique fixes in space the trace suchthat the trace appears fixed to the environmental positions independentof where the wearer is looking. So, for example, as the wearer's headturns, the trace appears fixed to the marked locations.

In embodiments, certain user positions may be known and thus identifiedin the FOV. For example, the shooter of the friendly fire trace 2108 maybe from a known friendly combatant and as such his location may beknown. The position may be known based on his GPS location based on amobile communication system on him, such as another HWC 102. In otherembodiments, the friendly combatant may be marked by another friendly.For example, if the friendly position in the environment is knownthrough visual contact or communicated information, a wearer of the HWC102 may use a gesture or external user interface 104 to mark thelocation. If a friendly combatant location is known the originatingposition of the friendly fire trace 2108 may be color coded or otherwisedistinguished from unidentified traces on the displayed digital content.Similarly, enemy fire traces 2104 may be color coded or otherwisedistinguished on the displayed digital content. In embodiments, theremay be an additional distinguished appearance on the displayed digitalcontent for unknown traces.

In addition to situationally associated trace appearance, the tracecolors or appearance may be different from the originating position tothe terminating position. This path appearance change may be based onthe mD signature. The mD signature may indicate that the bullet, forexample, is slowing as it propagates and this slowing pattern may bereflected in the FOV 2102 as a color or pattern change. This can createan intuitive understanding of wear the shooter is located. For example,the originating color may be red, indicative of high speed, and it maychange over the course of the trace to yellow, indicative of a slowingtrace. This pattern changing may also be different for a friendly, enemyand unknown combatant. The enemy may go blue to green for a friendlytrace, for example.

FIG. 21 illustrates an embodiment where the user sees the environmentthrough the FOV and may also see color coded traces, which are dependenton bullet speed and combatant type, where the traces are fixed inenvironmental positions independent on the wearer's perspective. Otherinformation, such as distance, range, range rings, time of day, date,engagement type (e.g. hold, stop firing, back away, etc.) may also bedisplayed in the FOV.

Another aspect of the present invention relates to mD radar techniquesthat trace and identify targets through other objects, such as walls(referred to generally as through wall mD), and visualization techniquesrelated therewith. FIG. 22 illustrates a through wall mD visualizationtechnique according to the principles of the present invention. Asdescribed herein elsewhere, the mD radar scanning the environment may belocal or remote from the wearer of a HWC 102. The mD radar may identifya target (e.g. a person) that is visible 2204 and then track the targetas he goes behind a wall 2208. The tracking may then be presented to thewearer of a HWC 102 such that digital content reflective of the targetand the target's movement, even behind the wall, is presented in the FOV2202 of the HWC 102. In embodiments, the target, when out of visiblesight, may be represented by an avatar in the FOV to provide the wearerwith imagery representing the target.

mD target recognition methods can identify the identity of a targetbased on the vibrations and other small movements of the target. Thiscan provide a personal signature for the target. In the case of humans,this may result in a personal identification of a target that has beenpreviously characterized. The cardio, heart beat, lung expansion andother small movements within the body may be unique to a person and ifthose attributes are pre-identified they may be matched in real time toprovide a personal identification of a person in the FOV 2202. Theperson's mD signatures may be determined based on the position of theperson. For example, the database of personal mD signature attributesmay include mD signatures for a person standing, sitting, laying down,running, walking, jumping, etc. This may improve the accuracy of thepersonal data match when a target is tracked through mD signaturetechniques in the field. In the event a person is personally identified,a specific indication of the person's identity may be presented in theFOV 2202. The indication may be a color, shape, shade, name, indicationof the type of person (e.g. enemy, friendly, etc.), etc. to provide thewearer with intuitive real time information about the person beingtracked. This may be very useful in a situation where there is more thanone person in an area of the person being tracked. If just one person inthe area is personally identified, that person or the avatar of thatperson can be presented differently than other people in the area.

FIG. 23 illustrates an mD scanned environment 2300. An mD radar may scanan environment in an attempt to identify objects in the environment. Inthis embodiment, the mD scanned environment reveals two vehicles 2302 aand 2302 b, en enemy combatant 2309, two friendly combatants 2308 a and2308 b and a shot trace 2318. Each of these objects may be personallyidentified or type identified. For example, the vehicles 2302 a and 2302b may be identified through the mD signatures as a tank and heavy truck.The enemy combatant 2309 may be identified as a type (e.g. enemycombatant) or more personally (e.g. by name). The friendly combatantsmay be identified as a type (e.g. friendly combatant) or more personally(e.g. by name). The shot trace 2318 may be characterized by type ofprojectile or weapon type for the projectile, for example.

FIG. 23a illustrates two separate HWC 102 FOV display techniquesaccording to the principles of the present invention. FOV 2312illustrates a map view 2310 where the mD scanned environment ispresented. Here, the wearer has a perspective on the mapped area so hecan understand all tracked targets in the area. This allows the wearerto traverse the area with knowledge of the targets. FOV 2312 illustratesa heads-up view to provide the wearer with an augmented reality styleview of the environment that is in proximity of the wearer.

An aspect of the present invention relates to suppression of extraneousor stray light. As discussed herein elsewhere, eyeglow and faceglow aretwo such artifacts that develop from such light. Eyeglow and faceglowcan be caused by image light escaping from the optics module. Theescaping light is then visible, particularly in dark environments whenthe user is viewing bright displayed images with the HWC. Light thatescapes through the front of the HWC is visible as eyeglow as it thatlight that is visible in the region of the user's eyes. Eyeglow canappear in the form of a small version of the displayed image that theuser is viewing. Light that escapes from the bottom of the HWC shinesonto the user's face, cheek or chest so that these portions of the userappear to glow. Eyeglow and faceglow can both increase the visibility ofthe user and highlight the use of the HWC, which may be viewednegatively by the user. As such, reducing eyeglow and faceglow isadvantageous. In combat situations (e.g. the mD trace presentationscenerios described herein) and certain gaming situations, thesuppression of extraneous or stray light is very important.

The disclosure relating to FIG. 6 shows an example where a portion ofthe image light passes through the combiner 602 such that the lightshines onto the user's face, thereby illuminating a portion of theuser's face in what is generally referred to herein as faceglow.Faceglow be caused by any portion of light from the HWC that illuminatesthe user's face.

An example of the source for the faceglow light can come from wide coneangle light associated with the image light incident onto the combiner602. Where the combiner can include a holographic mirror or a notchmirror in which the narrow bands of high reflectivity are matched towavelengths of light by the light source. The wide cone angle associatedwith the image light corresponds with the field of view provided by theHWC. Typically the reflectivity of holographic mirrors and notch mirrorsis reduced as the cone angle of the incident light is increased above 8degrees. As a result, for a field of view of 30 degrees, substantialimage light can pass through the combiner and cause faceglow.

FIG. 24 shows an illustration of a light trap 2410 for the faceglowlight. In this embodiment, an extension of the outer shield lens of theHWC is coated with a light absorbing material in the region where theconverging light responsible for faceglow is absorbed in a light trap2410. The light absorbing material can be black or it can be a filterdesigned to absorb only the specific wavelengths of light provided bythe light source(s) in the HWC. In addition, the surface of the lighttrap 2410 may be textured or fibrous to further improve the absorption.

FIG. 25 illustrates an optical system for a HWC that includes an outerabsorptive polarizer 2520 to block the faceglow light. In thisembodiment, the image light is polarized and as a result the lightresponsible for faceglow is similarly polarized. The absorptivepolarizer is oriented with a transmission axis such that the faceglowlight is absorbed and not transmitted. In this case, the rest of theimaging system in the HWC may not require polarized image light and theimage light may be polarized at any point before the combiner. Inembodiments, the transmission axis of the absorptive polarizer 2520 isoriented vertically so that external glare from water (S polarizedlight) is absorbed and correspondingly, the polarization of the imagelight is selected to be horizontal (S polarization). Consequently, imagelight that passes through the combiner 602 and is then incident onto theabsorptive polarizer 2520, is absorbed. In FIG. 25 the absorptivepolarizer 2520 is shown outside the shield lens, alternatively theabsorptive polarizer 2520 can be located inside the shield lens.

FIG. 26 illustrates an optical system for a HWC that includes a filmwith an absorptive notch filter 2620. In this case, the absorptive notchfilter absorbs narrow bands of light that are selected to match thelight provided by the optical system's light source. As a result, theabsorptive notch filter is opaque with respect to the faceglow light andis transparent to the remainder of the wavelengths included in thevisible spectrum so that the user has a clear view of the surroundingenvironment. A triple notch filter suitable for this approach isavailable from Iridian Spectral Technologies, Ottawa, ON:http://www.ilphotonics.com/cdv2/Iridian-Interference%20Filters/New%20filters/Triple%20Notch%20Filter.pdf

In embodiments, the combiner 602 may include a notch mirror coating toreflect the wavelengths of light in the image light and a notch filter2620 can be selected in correspondence to the wavelengths of lightprovided by the light source and the narrow bands of high reflectivityprovided by the notch mirror. In this way, image light that is notreflected by the notch mirror is absorbed by the notch filter 2620. Inembodiments of the invention the light source can provide one narrowband of light for a monochrome imaging or three narrow bands of lightfor full color imaging. The notch mirror and associated notch filterwould then each provide one narrow band or three narrow bands of highreflectivity and absorption respectively.

FIG. 27 includes a microlouver film 2750 to block the faceglow light.Microlouver film is sold by 3M as ALCF-P, for example and is typicallyused as a privacy filter for computer. Seehttp://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSuH8gc7nZxtUoY_xlY_eevUqe17zHvTSevTSeSSSSSS--&fn=ALCF-P_ABR2_Control_Film_DS.pdf Themicrolouver film transmits light within a somewhat narrow angle (e.g. 30degrees of normal and absorbs light beyond 30 degrees of normal). InFIG. 27, the microlouver film 2750 is positioned such that the faceglowlight 2758 is incident beyond 30 degrees from normal while thesee-through light 2755 is incident within 30 degrees of normal to themicrolouver film 2750. As such, the faceglow light 2758 is absorbed bythe microlouver film and the see-through light 2755 is transmitted sothat the user has a bright see-thru view of the surrounding environment.

We now turn back to a description of eye imaging technologies. Aspectsof the present invention relate to various methods of imaging the eye ofa person wearing the HWC 102. In embodiments, technologies for imagingthe eye using an optical path involving the “off” state and “no power”state, which is described in detail below, are described. Inembodiments, technologies for imaging the eye with opticalconfigurations that do not involve reflecting the eye image off of DLPmirrors is described. In embodiments, unstructured light, structuredlight, or controlled lighting conditions, are used to predict the eye'sposition based on the light reflected off of the front of the wearer'seye. In embodiments, a reflection of a presented digital content imageis captured as it reflects off of the wearer's eye and the reflectedimage may be processed to determine the quality (e.g. sharpness) of theimage presented. In embodiments, the image may then be adjusted (e.g.focused differently) to increase the quality of the image presentedbased on the image reflection.

FIGS. 28a, 28b and 28c show illustrations of the various positions ofthe DLP mirrors. FIG. 28a shows the DLP mirrors in the “on” state 2815.With the mirror in the “on” state 2815, illumination light 2810 isreflected along an optical axis 2820 that extends into the lower opticalmodule 204. FIG. 28b shows the DLP mirrors in the “off” state 2825. Withthe mirror in the “off” state 2825, illumination light 2810 is reflectedalong an optical axis 2830 that is substantially to the side of opticalaxis 2820 so that the “off” state light is directed toward a dark lighttrap as has been described herein elsewhere. FIG. 28c shows the DLPmirrors in a third position, which occurs when no power is applied tothe DLP. This “no power” state differs from the “on” and “off” states inthat the mirror edges are not in contact with the substrate and as suchare less accurately positioned. FIG. 28c shows all of the DLP mirrors inthe “no power” state 2835. The “no power” state is achieved bysimultaneously setting the voltage to zero for the “on” contact and“off” contact for a DLP mirror, as a result, the mirror returns to a nostress position where the DLP mirror is in the plane of the DLP platformas shown in FIG. 28c . Although not normally done, it is also possibleto apply the “no power” state to individual DLP mirrors. When the DLPmirrors are in the “no power” state they do not contribute imagecontent. Instead, as shown in FIG. 28c , when the DLP mirrors are in the“no power” state, the illumination light 2810 is reflected along anoptical axis 2840 that is between the optical axes 2820 and 2830 thatare respectively associated with the “on” and “off” states and as suchthis light doesn't contribute to the displayed image as a bright or darkpixel. This light can however contribute scattered light into the loweroptical module 204 and as a result the displayed image contrast can bereduced or artifacts can be created in the image that detract from theimage content. Consequently, it is generally desirable, in embodiments,to limit the time associated with the “no power” state to times whenimages are not displayed or to reduce the time associated with havingDLP mirrors in the “no power” state so that the affect of the scatteredlight is reduced.

FIG. 29 shows an embodiment of the invention that can be used fordisplaying digital content images to a wearer of the HWC 102 andcapturing images of the wearer's eye. In this embodiment, light from theeye 2971 passes back through the optics in the lower module 204, thesolid corrective wedge 2966, at least a portion of the light passesthrough the partially reflective layer 2960, the solid illuminationwedge 2964 and is reflected by a plurality of DLP mirrors on the DLP2955 that are in the “no power” state. The reflected light then passesback through the illumination wedge 2964 and at least a portion of thelight is reflected by the partially reflective layer 2960 and the lightis captured by the camera 2980.

For comparison, illuminating light rays 2973 from the light source 2958are also shown being reflected by the partially reflective layer 2960.Where the angle of the illuminating light 2973 is such that the DLPmirrors, when in the “on” state, reflect the illuminating light 2973 toform image light 2969 that substantially shares the same optical axis asthe light from the wearer's eye 2971. In this way, images of thewearer's eye are captured in a field of view that overlaps the field ofview for the displayed image content. In contrast, light reflected byDLP mirrors in the “off” state form dark light 2975 which is directedsubstantially to the side of the image light 2969 and the light from eye2971. Dark light 2975 is directed toward a light trap 2962 that absorbsthe dark light to improve the contrast of the displayed image as hasbeen described above in this specification.

In an embodiment, partially reflective layer 2960 is a reflectivepolarizer. The light that is reflected from the eye 2971 can then bepolarized prior to entering the corrective wedge 2966 (e.g. with anabsorptive polarizer between the upper module 202 and the lower module204), with a polarization orientation relative to the reflectivepolarizer that enables the light reflected from the eye 2971 tosubstantially be transmitted by the reflective polarizer. A quarter waveretarder layer 2957 is then included adjacent to the DLP 2955 (aspreviously disclosed in FIG. 3b ) so that the light reflected from theeye 2971 passes through the quarter wave retarder layer 2957 once beforebeing reflected by the plurality of DLP mirrors in the “no power” stateand then passes through a second time after being reflected. By passingthrough the quarter wave retarder layer 2957 twice, the polarizationstate of the light from the eye 2971 is reversed, such that when it isincident upon the reflective polarizer, the light from the eye 2971 isthen substantially reflected toward the camera 2980. By using apartially reflective layer 2960 that is a reflective polarizer andpolarizing the light from the eye 2971 prior to entering the correctivewedge 2964, losses attributed to the partially reflective layer 2960 arereduced.

FIG. 28c shows the case wherein the DLP mirrors are simultaneously inthe “no power” state, this mode of operation can be particularly usefulwhen the HWC 102 is first put onto the head of the wearer. When the HWC102 is first put onto the head of the wearer, it is not necessary todisplay an image yet. As a result, the DLP can be in a “no power” statefor all the DLP mirrors and an image of the wearer's eyes can becaptured. The captured image of the wearer's eye can then be compared toa database, using iris identification techniques, or other eye patternidentification techniques to determine, for example, the identity of thewearer.

In a further embodiment illustrated by FIG. 29 all of the DLP mirrorsare put into the “no power” state for a portion of a frame time (e.g.50% of a frame time for the displayed digital content image) and thecapture of the eye image is synchronized to occur at the same time andfor the same duration. By reducing the time that the DLP mirrors are inthe “no power” state, the time where light is scattered by the DLPmirrors being in the “no power” state is reduced such that the wearerdoesn't perceive a change in the displayed image quality. This ispossible because the DLP mirrors have a response time on the order ofmicroseconds while typical frame times for a displayed image are on theorder of 0.016 seconds. This method of capturing images of the wearer'seye can be used periodically to capture repetitive images of thewearer's eye. For example, eye images could be captured for 50% of theframe time of every 10^(th) frame displayed to the wearer. In anotherexample, eye images could be captured for 10% of the frame time of everyframe displayed to the wearer.

Alternately, the “no power” state can be applied to a subset of the DLPmirrors (e.g. 10% of the DLP mirrors) within while another subset is inbusy generating image light for content to be displayed. This enablesthe capture of an eye image(s) during the display of digital content tothe wearer. The DLP mirrors used for eye imaging can, for example, bedistributed randomly across the area of the DLP to minimize the impacton the quality of the digital content being displayed to the wearer. Toimprove the displayed image perceived by the wearer, the individual DLPmirrors put into the “no power” state for capturing each eye image, canbe varied over time such as in a random pattern, for example. In yet afurther embodiment, the DLP mirrors put into the “no power” state foreye imaging may be coordinated with the digital content in such a waythat the “no power” mirrors are taken from a portion of the image thatrequires less resolution.

In the embodiments of the invention as illustrated in FIGS. 9 and 29, inboth cases the reflective surfaces provided by the DLP mirrors do notpreserve the wavefront of the light from the wearer's eye so that theimage quality of captured image of the eye is somewhat limited. It maystill be useful in certain embodiments, but it is somewhat limited. Thisis due to the DLP mirrors not being constrained to be on the same plane.In the embodiment illustrated in FIG. 9, the DLP mirrors are tilted sothat they form rows of DLP mirrors that share common planes. In theembodiment illustrated in FIG. 29, the individual DLP mirrors are notaccurately positioned to be in the same plane since they are not incontact with the substrate. Examples of advantages of the embodimentsassociated with FIG. 29 are: first, the camera 2980 can be locatedbetween the DLP 2955 and the illumination light source 2958 to provide amore compact upper module 202. Second, the polarization state of thelight reflected from the eye 2971 can be the same as that of the imagelight 2969 so that the optical path of the light reflected from the eyeand the image light can be the same in the lower module 204.

FIG. 30 shows an illustration of an embodiment for displaying images tothe wearer and simultaneously capturing images of the wearer's eye,wherein light from the eye 2971 is reflected towards a camera 3080 bythe partially reflective layer 2960. The partially reflective layer 2960can be an optically flat layer such that the wavefront of the light fromthe eye 2971 is preserved and as a result, higher quality images of thewearer's eye can be captured. In addition, since the DLP 2955 is notincluded in the optical path for the light from the eye 2971, and theeye imaging process shown in FIG. 30 does not interfere with thedisplayed image, images of the wearer's eye can be capturedindependently (e.g. with independent of timing, impact on resolution, orpixel count used in the image light) from the displayed images.

In the embodiment illustrated in FIG. 30, the partially reflective layer2960 is a reflective polarizer, the illuminating light 2973 ispolarized, the light from the eye 2971 is polarized and the camera 3080is located behind a polarizer 3085. The polarization axis of theilluminating light 2973 and the polarization axis of the light from theeye are oriented perpendicular to the transmission axis of thereflective polarizer so that they are both substantially reflected bythe reflective polarizer. The illumination light 2973 passes through aquarter wave layer 2957 before being reflected by the DLP mirrors in theDLP 2955. The reflected light passes back through the quarter wave layer2957 so that the polarization states of the image light 2969 and darklight 2975 are reversed in comparison to the illumination light 2973. Assuch, the image light 2969 and dark light 2975 are substantiallytransmitted by the reflective polarizer. Where the DLP mirrors in the“on” state provide the image light 2969 along an optical axis thatextends into the lower optical module 204 to display an image to thewearer. At the same time, DLP mirrors in the “off” state provide thedark light 2975 along an optical axis that extends to the side of theupper optics module 202. In the region of the corrective wedge 2966where the dark light 2975 is incident on the side of the upper opticsmodule 202, an absorptive polarizer 3085 is positioned with it'stransmission axis perpendicular to the polarization axis of the darklight and parallel to the polarization axis of the light from the eye sothat the dark light 2975 is absorbed and the light from the eye 2971 istransmitted to the camera 3080.

FIG. 31 shows an illustration of another embodiment of a system fordisplaying images and simultaneously capturing image of the wearer's eyethat is similar to the one shown in FIG. 30. The difference in thesystem shown in FIG. 31 is that the light from the eye 2971 is subjectedto multiple reflections before being captured by the camera 3180. Toenable the multiple reflections, a mirror 3187 is provided behind theabsorptive polarizer 3185. Therefore, the light from the eye 2971 ispolarized prior to entering the corrective wedge 2966 with apolarization axis that is perpendicular to the transmission axis of thereflective polarizer that comprises the partially reflective layer 2960.In this way, the light from the eye 2971 is reflected first by thereflective polarizer, reflected second by the mirror 3187 and reflectedthird by the reflective polarizer before being captured by the camera3180. While the light from the eye 2971 passes through the absorptivepolarizer 3185 twice, since the polarization axis of the light from theeye 2971 is oriented parallel to the polarization axis of the light fromthe eye 2971, it is substantially transmitted by the absorptivepolarizer 3185. As with the system described in connection with FIG. 30,the system shown in FIG. 31 includes an optically flat partiallyreflective layer 2960 that preserves the wavefront of the light from theeye 2971 so that higher quality images of the wearer's eye can becaptured. Also, since the DLP 2955 is not included in the optical pathfor the light reflected from the eye 2971 and the eye imaging processshown in FIG. 31 does not interfere with the displayed image, images ofthe wearer's eye can be captured independently from the displayedimages.

FIG. 32 shows an illustration of a system for displaying images andsimultaneously capturing images of the wearer's eye that includes a beamsplitter plate 3212 comprised of a reflective polarizer, which is heldin air between the light source 2958, the DLP 2955 and the camera 3280.The illumination light 2973 and the light from the eye 2971 are bothpolarized with polarization axes that are perpendicular to thetransmission axis of the reflective polarizer. As a result, both theillumination light 2973 and the light from the eye 2971 aresubstantially reflected by the reflective polarizer. The illuminationlight 2873 is reflected toward the DLP 2955 by the reflective polarizerand split into image light 2969 and dark light 3275 depending on whetherthe individual DLP mirrors are respectively in the “on” state or the“off” state. By passing through the quarter wave layer 2957 twice, thepolarization state of the illumination light 2973 is reversed incomparison to the polarization state of the image light 2969 and thedark light 3275. As a result, the image light 2969 and the dark light3275 are then substantially transmitted by the reflective polarizer. Theabsorptive polarizer 3285 at the side of the beam splitter plate 3212has a transmission axis that is perpendicular to the polarization axisof the dark light 3275 and parallel to the polarization axis of thelight from the eye 2971 so that the dark light 3275 is absorbed and thelight from the eye 2971 is transmitted to the camera 3280. As in thesystem shown in FIG. 30, the system shown in FIG. 31 includes anoptically flat beam splitter plate 3212 that preserves the wavefront ofthe light from the eye 2971 so that higher quality images of thewearer's eye can be captured. Also, since the DLP 2955 is not includedin the optical path for the light from the eye 2971 and the eye imagingprocess shown in FIG. 31 does not interfere with the displayed image,images of the wearer's eye can be captured independently from thedisplayed images.

Eye imaging systems where the polarization state of the light from theeye 2971 needs to be opposite to that of the image light 2969 (as shownin FIGS. 30, 31 and 32), need to be used with lower modules 204 thatinclude combiners that will reflect both polarization states. As such,these upper modules 202 are best suited for use with the lower modules204 that include combiners that are reflective regardless ofpolarization state, examples of these lower modules are shown in FIGS.6, 8 a, 8 b, 8 c and 24-27.

In a further embodiment shown in FIG. 33, the partially reflective layer3360 is comprised of a reflective polarizer on the side facing theillumination light 2973 and a short pass dichroic mirror on the sidefacing the light from the eye 3371 and the camera 3080. Where the shortpass dichroic mirror is a dielectric mirror coating that transmitsvisible light and reflects infrared light. The partially reflectivelayer 3360 can be comprised of a reflective polarizer bonded to theinner surface of the illumination wedge 2964 and a short pass dielectricmirror coating on the opposing inner surface of the corrective wedge2966, wherein the illumination wedge 2964 and the corrective wedge 2966are then optically bonded together. Alternatively, the partiallyreflective layer 3360 can be comprised of a thin substrate that has areflective polarizer bonded to one side and a short pass dichroic mirrorcoating on the other side, where the partially reflective layer 3360 isthen bonded between the illumination wedge 2964 and the corrective wedge2966. In this embodiment, an infrared light is included to illuminatethe eye so that the light from the eye and the images captured of theeye are substantially comprised of infrared light. The wavelength of theinfrared light is then matched to the reflecting wavelength of theshortpass dichroic mirror and the wavelength that the camera can captureimages, for example an 800 nm wavelength can be used. In this way, theshort pass dichroic mirror transmits the image light and reflects thelight from the eye. The camera 3080 is then positioned at the side ofthe corrective wedge 2966 in the area of the absorbing light trap 3382,which is provided to absorb the dark light 2975. By positioning thecamera 3080 in a depression in the absorbing light trap 3382, scatteringof the dark light 2975 by the camera 3080 can be reduced so that highercontrast images can be displayed to the wearer. An advantage of thisembodiment is that the light from the eye need not be polarized, whichcan simplify the optical system and increase efficiency for the eyeimaging system.

In yet another embodiment shown in FIG. 32a a beam splitter plate 3222is comprised of a reflective polarizer on the side facing theillumination light 2973 and a short pass dichroic mirror on the sidefacing the light from the eye 3271 and the camera 3280. An absorbingsurface 3295 is provided to trap the dark light 3275 and the camera 3280is positioned in an opening in the absorbing surface 3295. In this waythe system of FIG. 32 can be made to function with unpolarized lightfrom the eye 3271.

In embodiments directed to capturing images of the wearer's eye, lightto illuminate the wearer's eye can be provided by several differentsources including: light from the displayed image (i.e. image light);light from the environment that passes through the combiner or otheroptics; light provided by a dedicated eye light, etc. FIGS. 34 and 34 ashow illustrations of dedicated eye illumination lights 3420. FIG. 34shows an illustration from a side view in which the dedicatedillumination eye light 3420 is positioned at a corner of the combiner3410 so that it doesn't interfere with the image light 3415. Thededicated eye illumination light 3420 is pointed so that the eyeillumination light 3425 illuminates the eyebox 3427 where the eye 3430is located when the wearer is viewing displayed images provided by theimage light 3415. FIG. 34a shows an illustration from the perspective ofthe eye of the wearer to show how the dedicated eye illumination light3420 is positioned at the corner of the combiner 3410. While thededicated eye illumination light 3420 is shown at the upper left cornerof the combiner 3410, other positions along one of the edges of thecombiner 3410, or other optical or mechanical components, are possibleas well. In other embodiments, more than one dedicated eye light 3420with different positions can be used. In an embodiment, the dedicatedeye light 3420 is an infrared light that is not visible by the wearer(e.g. 800 nm) so that the eye illumination light 3425 doesn't interferewith the displayed image perceived by the wearer.

FIG. 35 shows a series of illustrations of captured eye images that showthe eye glint (i.e. light that reflects off the front of the eye)produced by a dedicated eye light. In this embodiment of the invention,captured images of the wearer's eye are analyzed to determine therelative positions of the iris 3550, pupil, or other portion of the eye,and the eye glint 3560. The eye glint is a reflected image of thededicated eye light 3420 when the dedicated light is used. FIG. 35illustrates the relative positions of the iris 3550 and the eye glint3560 for a variety of eye positions. By providing a dedicated eye light3420 in a fixed position, combined with the fact that the human eye isessentially spherical, or at least a reliably repeatable shape, the eyeglint provides a fixed reference point against which the determinedposition of the iris can be compared to determine where the wearer islooking, either within the displayed image or within the see-throughview of the surrounding environment. By positioning the dedicated eyelight 3420 at a corner of the combiner 3410, the eye glint 3560 isformed away from the iris 3550 in the captured images. As a result, thepositions of the iris and the eye glint can be determined more easilyand more accurately during the analysis of the captured images, sincethey do not interfere with one another. In a further embodiment, thecombiner includes an associated cut filter that prevents infrared lightfrom the environment from entering the HWC and the camera is an infraredcamera, so that the eye glint is only provided by light from thededicated eye light. For example, the combiner can include a low passfilter that passes visible light while absorbing infrared light and thecamera can include a high pass filter that absorbs visible light whilepassing infrared light.

In an embodiment of the eye imaging system, the lens for the camera isdesigned to take into account the optics associated with the uppermodule 202 and the lower module 204. This is accomplished by designingthe camera to include the optics in the upper module 202 and optics inthe lower module 204, so that a high MTF image is produced, at the imagesensor in the camera, of the wearer's eye. In yet a further embodiment,the camera lens is provided with a large depth of field to eliminate theneed for focusing the camera to enable sharp image of the eye to becaptured. Where a large depth of field is typically provided by a highf/# lens (e.g. f/#>5). In this case, the reduced light gatheringassociated with high f/# lenses is compensated by the inclusion of adedicated eye light to enable a bright image of the eye to be captured.Further, the brightness of the dedicated eye light can be modulated andsynchronized with the capture of eye images so that the dedicated eyelight has a reduced duty cycle and the brightness of infrared light onthe wearer's eye is reduced.

In a further embodiment, FIG. 36a shows an illustration of an eye imagethat is used to identify the wearer of the HWC. In this case, an imageof the wearer's eye 3611 is captured and analyzed for patterns ofidentifiable features 3612. The patterns are then compared to a databaseof eye images to determine the identity of the wearer. After theidentity of the wearer has been verified, the operating mode of the HWCand the types of images, applications, and information to be displayed,can be adjusted and controlled in correspondence to the determinedidentity of the wearer. Examples of adjustments to the operating modedepending on who the wearer is determined to be or not be include:making different operating modes or feature sets available, shuttingdown or sending a message to an external network, allowing guestfeatures and applications to run, etc.

FIG. 36b is an illustration of another embodiment using eye imaging, inwhich the sharpness of the displayed image is determined based on theeye glint produced by the reflection of the displayed image from thewearer's eye surface. By capturing images of the wearer's eye 3611, aneye glint 3622, which is a small version of the displayed image can becaptured and analyzed for sharpness. If the displayed image isdetermined to not be sharp, then an automated adjustment to the focus ofthe HWC optics can be performed to improve the sharpness. This abilityto perform a measurement of the sharpness of a displayed image at thesurface of the wearer's eye can provide a very accurate measurement ofimage quality. Having the ability to measure and automatically adjustthe focus of displayed images can be very useful in augmented realityimaging where the focus distance of the displayed image can be varied inresponse to changes in the environment or changes in the method of useby the wearer.

An aspect of the present invention relates to controlling the HWC 102through interpretations of eye imagery. In embodiments, eye-imagingtechnologies, such as those described herein, are used to capture an eyeimage or series of eye images for processing. The image(s) may beprocess to determine a user intended action, an HWC predeterminedreaction, or other action. For example, the imagery may be interpretedas an affirmative user control action for an application on the HWC 102.Or, the imagery may cause, for example, the HWC 102 to react in apre-determined way such that the HWC 102 is operating safely,intuitively, etc.

FIG. 37 illustrates a eye imagery process that involves imaging the HWC102 wearer's eye(s) and processing the images (e.g. through eye imagingtechnologies described herein) to determine in what position 3702 theeye is relative to it's neutral or forward looking position and/or theFOV 3708. The process may involve a calibration step where the user isinstructed, through guidance provided in the FOV of the HWC 102, to lookin certain directions such that a more accurate prediction of the eyeposition relative to areas of the FOV can be made. In the event thewearer's eye is determined to be looking towards the right side of theFOV 3708 (as illustrated in FIG. 37, the eye is looking out of the page)a virtual target line may be established to project what in theenvironment the wearer may be looking towards or at. The virtual targetline may be used in connection with an image captured by camera on theHWC 102 that images the surrounding environment in front of the wearer.In embodiments, the field of view of the camera capturing thesurrounding environment matches, or can be matched (e.g. digitally), tothe FOV 3708 such that making the comparison is made more clear. Forexample, with the camera capturing the image of the surroundings in anangle that matches the FOV 3708 the virtual line can be processed (e.g.in 2d or 3d, depending on the camera images capabilities and/or theprocessing of the images) by projecting what surrounding environmentobjects align with the virtual target line. In the event there aremultiple objects along the virtual target line, focal planes may beestablished corresponding to each of the objects such that digitalcontent may be placed in an area in the FOV 3708 that aligns with thevirtual target line and falls at a focal plane of an intersectingobject. The user then may see the digital content when he focuses on theobject in the environment, which is at the same focal plane. Inembodiments, objects in line with the virtual target line may beestablished by comparison to mapped information of the surroundings.

In embodiments, the digital content that is in line with the virtualtarget line may not be displayed in the FOV until the eye position is inthe right position. This may be a predetermined process. For example,the system may be set up such that a particular piece of digital content(e.g. an advertisement, guidance information, object information, etc.)will appear in the event that the wearer looks at a certain object(s) inthe environment. A virtual target line(s) may be developed thatvirtually connects the wearer's eye with an object(s) in the environment(e.g. a building, portion of a building, mark on a building, gpslocation, etc.) and the virtual target line may be continually updateddepending on the position and viewing direction of the wearer (e.g. asdetermined through GPS, e-compass, IMU, etc.) and the position of theobject. When the virtual target line suggests that the wearer's pupil issubstantially aligned with the virtual target line or about to bealigned with the virtual target line, the digital content may bedisplayed in the FOV 3704.

In embodiments, the time spent looking along the virtual target lineand/or a particular portion of the FOV 3708 may indicate that the weareris interested in an object in the environment and/or digital contentbeing displayed. In the event there is no digital content beingdisplayed at the time a predetermined period of time is spent looking ata direction, digital content may be presented in the area of the FOV3708. The time spent looking at an object may be interpreted as acommand to display information about the object, for example. In otherembodiments, the content may not relate to the object and may bepresented because of the indication that the person is relativelyinactive. In embodiments, the digital content may be positioned inproximity to the virtual target line, but not in-line with it such thatthe wearer's view of the surroundings are not obstructed but informationcan augment the wearer's view of the surroundings. In embodiments, thetime spent looking along a target line in the direction of displayeddigital content may be an indication of interest in the digital content.This may be used as a conversion event in advertising. For example, anadvertiser may pay more for an add placement if the wearer of the HWC102 looks at a displayed advertisement for a certain period of time. Assuch, in embodiments, the time spent looking at the advertisement, asassessed by comparing eye position with the content placement, targetline or other appropriate position may be used to determine a rate ofconversion or other compensation amount due for the presentation.

An aspect of the invention relates to removing content from the FOV ofthe HWC 102 when the wearer of the HWC 102 apparently wants to view thesurrounding environments clearly. FIG. 38 illustrates a situation whereeye imagery suggests that the eye has or is moving quickly so thedigital content 3804 in the FOV 3808 is removed from the FOV 3808. Inthis example, the wearer may be looking quickly to the side indicatingthat there is something on the side in the environment that has grabbedthe wearer's attention. This eye movement 3802 may be captured througheye imaging techniques (e.g. as described herein) and if the movementmatches a predetermined movement (e.g. speed, rate, pattern, etc.) thecontent may be removed from view. In embodiments, the eye movement isused as one input and HWC movements indicated by other sensors (e.g. IMUin the HWC) may be used as another indication. These various sensormovements may be used together to project an event that should cause achange in the content being displayed in the FOV.

Another aspect of the present invention relates to determining a focalplane based on the wearer's eye convergence. Eyes are generallyconverged slightly and converge more when the person focuses onsomething very close. This is generally referred to as convergence. Inembodiments, convergence is calibrated for the wearer. That is, thewearer may be guided through certain focal plane exercises to determinehow much the wearer's eyes converge at various focal planes and atvarious viewing angles. The convergence information may then be storedin a database for later reference. In embodiments, a general table maybe used in the event there is no calibration step or the person skipsthe calibration step. The two eyes may then be imaged periodically todetermine the convergence in an attempt to understand what focal planethe wearer is focused on. In embodiments, the eyes may be imaged todetermine a virtual target line and then the eye's convergence may bedetermined to establish the wearer's focus, and the digital content maybe displayed or altered based thereon.

FIG. 39 illustrates a situation where digital content is moved 3902within one or both of the FOVs 3908 and 3910 to align with theconvergence of the eyes as determined by the pupil movement 3904. Bymoving the digital content to maintain alignment, in embodiments, theoverlapping nature of the content is maintained so the object appearsproperly to the wearer. This can be important in situations where 3Dcontent is displayed.

An aspect of the present invention relates to controlling the HWC 102based on events detected through eye imaging. A wearer winking,blinking, moving his eyes in a certain pattern, etc. may, for example,control an application of the HWC 102. Eye imaging (e.g. as describedherein) may be used to monitor the eye(s) of the wearer and once apre-determined pattern is detected an application control command may beinitiated.

An aspect of the invention relates to monitoring the health of a personwearing a HWC 102 by monitoring the wearer's eye(s). Calibrations may bemade such that the normal performance, under various conditions (e.g.lighting conditions, image light conditions, etc.) of a wearer's eyesmay be documented. The wearer's eyes may then be monitored through eyeimaging (e.g. as described herein) for changes in their performance.Changes in performance may be indicative of a health concern (e.g.concussion, brain injury, stroke, loss of blood, etc.). If detected thedata indicative of the change or event may be communicated from the HWC102.

Aspects of the present invention relate to security and access ofcomputer assets (e.g. the HWC itself and related computer systems) asdetermined through eye image verification. As discussed hereinelsewhere, eye imagery may be compared to known person eye imagery toconfirm a person's identity. Eye imagery may also be used to confirm theidentity of people wearing the HWCs 102 before allowing them to linktogether or share files, streams, information, etc.

Although embodiments of HWC have been described in language specific tofeatures, systems, computer processes and/or methods, the appendedclaims are not necessarily limited to the specific features, systems,computer processes and/or methods described. Rather, the specificfeatures, systems, computer processes and/or and methods are disclosedas non-limited example implementations of HWC. All documents referencedherein are hereby incorporated by reference.

We claim:
 1. A head-worn computer, comprising: a camera adapted tocapture a plurality of reflected images of an eye of a person wearingthe head-worn computer to determine a plurality of positions of the eye,wherein the head-worn computer comprises a see-through displaydisplaying digitally presented content, wherein the camera is positionedto capture the reflected images of the eye through a common optical axiswith the digitally presented content in-line with the eye of the user;and a processor adapted to determine a rate of position change statisticdescribing a rate of positional change of the eye based on the pluralityof reflected images, the processor further adapted to remove thedigitally presented content from a field of view of the see-throughdisplay if the rate of positional change exceeds a predeterminedthreshold.
 2. The head-worn computer of claim 1, wherein the camera islocated proximate the see-through display.
 3. The head-worn computer ofclaim 1, wherein the see-through display is a reflective display and thereflected image of the eye of the person reflects off of the see-throughdisplay prior to being captured by the camera.
 4. The head-worn computerof claim 1, further comprising a reflective surface positioned betweenthe see-through display and the camera, wherein the camera captures thereflected image of the eye of the person after it reflects off of thereflective surface.
 5. The head-worn computer of claim 1, wherein thesee-through display is a front lit reflective image display.
 6. Thehead-worn computer of claim 1, wherein the see-through display is anemissive display.
 7. The head-worn computer of claim 1, wherein thedigitally presented content removed from the see-through display is suchthat the person perceives the digitally presented content as a 3D image.